Once T146225 is done, we should add support for language specific UCA collations to the installer (and make them the default for non-English languages). For example, if someone sets their wiki's language to French in the first step of the installer, it should add the following options to the Category Collation section of the installer:
🔘 Customized UCA (fr)
🔘 Customized UCA (fr) with numeric
"Customized UCA (fr) with numeric" should be the default choice in this case. (Unfortunately, we don't have a reliable way to get the name of the language from the language code in the user's language during the installation process. Thus, we can't label it "UCA French", for example.)
The 2 additional options should only be provided if the wiki's server has the PHP intl library installed, the user has chosen a language other than English, and the language they have chosen is supported by MediaWiki's IcuCollation class (See https://www.mediawiki.org/wiki/Manual:$wgCategoryCollation#Language-specific_collations).