Oh! I remember joining a Gmod server and some of the files it downloaded were for Wire, I wonder if I can find the mod in the game's folder.
well, you aren't gonna get an SVN client from a gmod server
an SVN client, usually TortoiseSVN, was usually used to get Wire, and I think PHX, and probably some other mods, until the steam workshop ended up replacing manually downloaded mods
if you never manually downloaded them, you wouldn't have it
but apparently, according to the last two posters, it's just a windows thing anyway
and now that I think about it, it may actually be related to onedrive
did any of the icons look like this?