locale_get_display_name does not work as expected by default in Alpine Linux 3.16 based PHP images

The latest PHP images based on Alpine Linux now use Alpine Linux v3.16.

In v3.16, Alpine Linux has split the ICU package in two: icu-data-en and icu-data-full.

Only the icu-data-en package is now installed by default. The Alpine Linux changelog mentions this as well:

icu-libs only installs icu-data-en. If additional language support is required, icu-data-full needs to be installed manually. 

# apk list | grep -i icu
icu-libs-71.1-r2 x86_64 {icu} (MIT ICU Unicode-TOU) [installed]
icu-data-en-71.1-r2 x86_64 {icu} (MIT ICU Unicode-TOU) [installed]

This results in the following code not working as expected:

<?php

echo locale_get_display_name('ja', 'ja');

This now yields the output Japanese instead the expected 日本語. Other locale-related methods will probably also be affected.

Would the Alpine-based PHP images want to include the icu-data-full package by default? Or is this package expected/intended to be not installed by default?

See

• https://github.com/php/php-src/issues/8656
• https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.16.0#ICU_data_split

Start with the Alpine-based PHP image definitions and the APK packages they install. Reproduce locale_get_display_name('ja', 'ja') in an Alpine 3.16-based PHP image, then verify the selected package behavior and document or implement the maintainer-approved default for full ICU locale data.