hope VLC on android could read subs from zip/rar/7z directly.
Subtitles usually are inside archive files on disks today, for both convenience and clear for folders.
If VLC is playing video from the network(smb/http), the server end need to extract all subtitles files and match those filenames to the video file/pathname.
It's easy to read ass/srt from zip(a little diffculty from rar/7z) for the video player. and this is very helpful for mobile devices(since desktop could drag ass/srt to the video player from opened archive files by explorer or 7z manager or winrar).