Sep_September_abbreviation etc.

Are snippets like the following supposed do be translated into the corresponding abbreviations in the language of the translation (That has already been done in the odds and ends section, so it seems superfluous.), or are they some sort of computer code that should be left alone?

Sep_September_abbreviation
M_Monday_initial

And what could this be? Is it to determine if points or commas should be used for decimals?
number_format_decimal_point

They all show up in the list of not yet translated, but the "where" links are dead.

If these are the same ones I am thinking of, they should not be in the translation UI at all - these are the names of the entries that are translated elsewhere. So they should stay as they are.

That's what I guessed. I'll leave them as is then.
They are found quite high up on the epo.-site list of nontranslated text.

http://epo.librarything.com/translate.php?remaining=1

I remember them from the BG site when I was dealing with some translations there -- there were quite a few of those at one point - a lot of them were cleaned, some remained. :)