According to my memory of old bug reports we used to have the ability to modify cached data (as in cached on disk) without them being resent by server; that was exploited (by editing trader prefabs to allow building for example) so that was taken away.
But there are times when servers provide their own localization.txt (or a part of it for modded content), which could be using one specific language localized or localizing everything without player wanting it.
There are two radical sides of it of course:
1) some people might want to play only with players that speak the same language. Dunno why, but you have a right to wish for it.
2) some people don't care who to play with (on a server); they just enjoy the company
Pretty sure you could just allow servers to force localization.txt separately and that would fix both cases.
Either way, even if server chooses to force localization.txt contents, there is no harm in storing local copy on player side. Or making a client-side-only console command to dump its contents (I kinda pity that all console commands require server-side priviliges).
Currently, client side already does keep some files so it shouldn't be a costly change.
But there are times when servers provide their own localization.txt (or a part of it for modded content), which could be using one specific language localized or localizing everything without player wanting it.
There are two radical sides of it of course:
1) some people might want to play only with players that speak the same language. Dunno why, but you have a right to wish for it.
2) some people don't care who to play with (on a server); they just enjoy the company
Pretty sure you could just allow servers to force localization.txt separately and that would fix both cases.
Either way, even if server chooses to force localization.txt contents, there is no harm in storing local copy on player side. Or making a client-side-only console command to dump its contents (I kinda pity that all console commands require server-side priviliges).
Currently, client side already does keep some files so it shouldn't be a costly change.