In cases, when localized media files are provided by some languages,
we need to use 'gnome.yelp ()' with 'symlink_media: false' which
copies all files from 'C' locale in addition to the localized
media. This wastes storage space. The alternative is to use
'symlink_media: true' which symlinks entirely to 'C' media files
ignoring localized media files.
As a middle ground, if the localized media file exists in the source
tree for a language, we use that file rather than symlinking to 'C'
media with the same filename even when 'symlink_media: true'. This
saves storage space.
If there are no localized media files in non-C language, the existing
behaviour is maintained.