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No, installed lang-packs are as expected (however I still don’t understand preference of substractive install everything, prune unnecessary over additive install minimal, add necessary as to langpacks). On a freshly-installed Ubuntu Disco from official ISO, with Polish lang-pack selected on install:

# aptitude search '~i~nlanguage-'
i   language-pack-en                                          - translation updates for language English                            
i   language-pack-en-base                                     - translations for language English                                   
i   language-pack-gnome-en                                    - GNOME translation updates for language English                      
i   language-pack-gnome-en-base                               - GNOME translations for language English                             
i   language-pack-gnome-pl                                    - GNOME translation updates for language Polish                       
i A language-pack-gnome-pl-base                               - GNOME translations for language Polish                              
i   language-pack-pl                                          - translation updates for language Polish                             
i A language-pack-pl-base                                     - translations for language Polish                                    
i A language-selector-common                                  - Language selector for Ubuntu                                        
i A language-selector-gnome                                   - Language selector for Ubuntu                                        

The core of annoyance I mentioned is rather due to:

$> LANG=en_US apt-cache depends ubuntu-desktop
[...]
Recommends: fonts-indic
Recommends: fonts-kacst-one
Recommends: fonts-khmeros-core
Recommends: fonts-lao
Recommends: fonts-lklug-sinhala
Recommends: fonts-noto-cjk
Recommends: fonts-noto-color-emoji
Recommends: fonts-sil-abyssinica
Recommends: fonts-sil-padauk
Recommends: fonts-thai-tlwg
Recommends: fonts-tibetan-machine
[...]

which results in this (due to treating recommends as dependencies, at least during system install):

# aptitude search '~i~nfonts-'
i A fonts-beng                                                - Metapackage to install Bengali and Assamese fonts                   
i A fonts-beng-extra                                          - TrueType fonts for Bengali language                                 
i A fonts-dejavu-core                                         - Czcionki pochodzÄ…ce z rodziny Vera z dodatkowymi znakami            
i A fonts-deva                                                - Meta package to install all Devanagari fonts                        
i A fonts-deva-extra                                          - Free fonts for Devanagari script                                    
i A fonts-droid-fallback                                      - handheld device font with extensive style and language support (fall
i A fonts-freefont-ttf                                        - Czcionki TrueType: Serif, Sans i Mono z zestawu Freefont            
i A fonts-gargi                                               - OpenType Devanagari font                                            
i A fonts-gubbi                                               - Gubbi free font for Kannada script                                  
i A fonts-gujr                                                - Meta package to install all Gujarati fonts                          
i A fonts-gujr-extra                                          - Free fonts for Gujarati script                                      
i A fonts-guru                                                - Meta package to install all Punjabi fonts                           
i A fonts-guru-extra                                          - Free fonts for Punjabi language                                     
i   fonts-indic                                               - Meta package to install all Indian language fonts                   
i A fonts-kacst                                               - KACST free TrueType Arabic fonts                                    
i A fonts-kacst-one                                           - TrueType font designed for Arabic language                          
i A fonts-kalapi                                              - Kalapi Gujarati Unicode font                                        
i A fonts-khmeros-core                                        - KhmerOS Unicode fonts for the Khmer language of Cambodia            
i A fonts-knda                                                - Meta package for Kannada fonts                                      
i A fonts-lao                                                 - TrueType font for Lao language                                      
i A fonts-liberation                                          - Fonty o tych samych wymiarach jak Times, Arial i Courier            
i A fonts-liberation2                                         - Fonts with the same metrics as Times, Arial and Courier (v2)        
i A fonts-lklug-sinhala                                       - Unicode Sinhala font by Lanka Linux User Group                      
i A fonts-lohit-beng-assamese                                 - Lohit TrueType font for Assamese Language                           
i A fonts-lohit-beng-bengali                                  - Lohit TrueType font for Bengali Language                            
i A fonts-lohit-deva                                          - Lohit TrueType font for Devanagari script                           
i A fonts-lohit-gujr                                          - Lohit TrueType font for Gujarati Language                           
i A fonts-lohit-guru                                          - Lohit TrueType font for Punjabi Language                            
i A fonts-lohit-knda                                          - Lohit TrueType font for Kannada Language                            
i A fonts-lohit-mlym                                          - Lohit TrueType font for Malayalam Language                          
i A fonts-lohit-orya                                          - Lohit TrueType font for Oriya Language                              
i A fonts-lohit-taml                                          - Lohit TrueType font for Tamil Language                              
i A fonts-lohit-taml-classical                                - Lohit Tamil TrueType fonts for Tamil script                         
i A fonts-lohit-telu                                          - Lohit TrueType font for Telugu Language                             
i A fonts-mlym                                                - Meta package to install all Malayalam fonts                         
i A fonts-nakula                                              - Free Unicode compliant Devanagari font                              
i A fonts-navilu                                              - Handwriting font for Kannada                                        
i A fonts-noto-cjk                                            - "No Tofu" font families with large Unicode coverage (CJK regular and
i A fonts-noto-color-emoji                                    - color emoji font from Google                                        
i A fonts-noto-mono                                           - "No Tofu" monospaced font family with large Unicode coverage        
i A fonts-opensymbol                                          - Font OpenSymbol w formacie TrueType                                 
i A fonts-orya                                                - Meta package to install all Oriya fonts                             
i A fonts-orya-extra                                          - Free fonts for Oriya script                                         
i A fonts-pagul                                               - Free TrueType font for the Sourashtra language                      
i A fonts-sahadeva                                            - Free Unicode compliant Devanagari font                              
i A fonts-samyak-deva                                         - Samyak TrueType font for Devanagari script                          
i A fonts-samyak-gujr                                         - Samyak TrueType font for Gujarati language                          
i A fonts-samyak-mlym                                         - Samyak TrueType font for Malayalam language                         
i A fonts-samyak-taml                                         - Samyak TrueType font for Tamil language                             
i A fonts-sarai                                               - truetype font for devanagari script                                 
i A fonts-sil-abyssinica                                      - smart Unicode font for Ethiopian and Erythrean scripts (Amharic et a
i A fonts-sil-padauk                                          - Burmese Unicode 6 truetype font with OT and Graphite support        
i A fonts-smc                                                 - Metapackage for various TrueType fonts for Malayalam Language       
i A fonts-smc-anjalioldlipi                                   - AnjaliOldLipi malayalam font                                        
i A fonts-smc-chilanka                                        - Chilanka malayalam font                                             
i A fonts-smc-dyuthi                                          - Dyuthi malayalam font                                               
i A fonts-smc-karumbi                                         - Karumbi malayalam font                                              
i A fonts-smc-keraleeyam                                      - Keraleeyam malayalam font                                           
i A fonts-smc-manjari                                         - Manjari malayalam font                                              
i A fonts-smc-meera                                           - Meera malayalam font                                                
i A fonts-smc-rachana                                         - Rachana malayalam font                                              
i A fonts-smc-raghumalayalamsans                              - RaghuMalayalamSans malayalam font                                   
i A fonts-smc-suruma                                          - Suruma malayalam font                                               
i A fonts-smc-uroob                                           - Uroob malayalam font                                                
i A fonts-taml                                                - Meta package to install all Tamil fonts                             
i A fonts-telu                                                - Meta package to install all Telugu fonts                            
i A fonts-telu-extra                                          - Free fonts for Telugu script                                        
i A fonts-thai-tlwg                                           - Thai fonts maintained by TLWG (metapackage)                         
i A fonts-tibetan-machine                                     - font for Tibetan, Dzongkha and Ladakhi (OpenType Unicode)           
i A fonts-tlwg-garuda                                         - Thai Garuda font (dependency package)                               
i A fonts-tlwg-garuda-ttf                                     - Thai Garuda TrueType font                                           
i A fonts-tlwg-kinnari                                        - Thai Kinnari font (dependency package)                              
i A fonts-tlwg-kinnari-ttf                                    - Thai Kinnari TrueType font                                          
i A fonts-tlwg-laksaman                                       - Thai Laksaman font (dependency package)                             
i A fonts-tlwg-laksaman-ttf                                   - Thai Laksaman TrueType font                                         
i A fonts-tlwg-loma                                           - Thai Loma font (dependency package)                                 
i A fonts-tlwg-loma-ttf                                       - Thai Loma TrueType font                                             
i A fonts-tlwg-mono                                           - Thai TlwgMono font (dependency package)                             
i A fonts-tlwg-mono-ttf                                       - Thai TlwgMono TrueType font                                         
i A fonts-tlwg-norasi                                         - Thai Norasi font (dependency package)                               
i A fonts-tlwg-norasi-ttf                                     - Thai Norasi TrueType font                                           
i A fonts-tlwg-purisa                                         - Thai Purisa font (dependency package)                               
i A fonts-tlwg-purisa-ttf                                     - Thai Purisa TrueType font                                           
i A fonts-tlwg-sawasdee                                       - Thai Sawasdee font (dependency package)                             
i A fonts-tlwg-sawasdee-ttf                                   - Thai Sawasdee TrueType font                                         
i A fonts-tlwg-typewriter                                     - Thai TlwgTypewriter font (dependency package)                       
i A fonts-tlwg-typewriter-ttf                                 - Thai TlwgTypewriter TrueType font                                   
i A fonts-tlwg-typist                                         - Thai TlwgTypist font (dependency package)                           
i A fonts-tlwg-typist-ttf                                     - Thai TlwgTypist TrueType font                                       
i A fonts-tlwg-typo                                           - Thai TlwgTypo font (dependency package)                             
i A fonts-tlwg-typo-ttf                                       - Thai TlwgTypo TrueType font                                         
i A fonts-tlwg-umpush                                         - Thai Umpush font (dependency package)                               
i A fonts-tlwg-umpush-ttf                                     - Thai Umpush TrueType font                                           
i A fonts-tlwg-waree                                          - Thai Waree font (dependency package)                                
i A fonts-tlwg-waree-ttf                                      - Thai Waree TrueType font                                            
i A fonts-ubuntu                                              - sans-serif font set from Ubuntu                                     
i A fonts-yrsa-rasa                                           - Open-source, libre fonts for Latin + Gujarati                       
i A xfonts-base                                               - standard fonts for X                                                
i A xfonts-encodings                                          - Kodowanie czcionek z X.Org                                          
i A xfonts-scalable                                           - scalable fonts for X                                                
i A xfonts-utils                                              - Narzędzia do zarządzania czcionkami w X-ach                         

Again, fresh install, Polish locale, just added aptitude to filter installed packages.