In lists, ../show/LIST_NUMBER/und redirects to /und/und and /jpn redirects to /und/jpn about tatoeba2

[Yorwba]

This is intentional, not a bug. A new parameter was added to the URL to allow filtering the list by language, and URLs missing that parameter redirect to the new URL with the language set to undefined.

[ckjpn]

It doesn't matter to me really since the old links still work,

However, it seems strange to have the "und" repeated.
/und/und

I assume that perhaps "und" stands for "undetermined," though until now I just always thought it must be based on another language and meant "all."

So, I guess "/und/jpn" means "undetermined" and then "Japanese."

I wonder why this change was felt necessary.