a sign is +/- or something seen in traffc, the word symbol seems to fit better.

I know all the rest is const and I made it const, but sanderd17 has convinced me some time ago that var is better for mods, so they can change it from an external file

Comments having the exact same character composition a the variable name should be removed.
Comments should give information (information implies uniqueness).

So if we want to keep this JSdoc format, it should explain in which situation this icon is used.

for now i split buddy names by "|" sign if thinks is no allowed in names in lobby.

It's a design decision whether the player will be shown as a buddy of oneself. Might make the code shorter if not caring about this, but we can keep that design decision.

I'd rather check for g_Username == player.name || g_UserBuddies.indexOf(player.name) != -1 though instead of the concat

as suggest by vladis seperat sort and filter command.

i wanted to prefer here when selecting buddy sorting buddy then presence [online,away,playing..] and then name in this prio if its ok.

Using the alpha transparency to hide the sign we later add is pointless if we can just not add anything instead.
\n somewhere since we ought to have 80 characters per line at most (http://trac.wildfiregames.com/wiki/Coding_Conventions) and really not more than 120 if possible

im for showing username as buddied alltime

tabs instead of spaces

Those hardcoded numbers are bad. People should be able to only change the XML without having to change the JS numbers. Write code to compute the numbers dynamically.

Why do we have this code at all, the button should always be visible.

missing spaces at =

.hidden = can be pulled out of the if statement to reduce code

let? also unused, so delete

Should have an early return, so that the user can't be a buddy of himself.

selected == -1 if no player has been selected before can't occur with your patch on init becaues you hide the button, but instead the button should always be visible and just not do anything if the player is not selected.

However selected == -1 can occur if a player is selected but goes offline!

g_UserBuddies.join(",") duplication can be reduced

nice work u applied my status order for gamelists thx!

hasBuddies (in accordance with isBuddy)

If a player doesn't have a name, that's a serious bug outside of this code.
If we want this code to be immune towards players who register broken games, then this should be in the code that parses

just save the name without rating once, then we can get rid of that rating removal function altogether

prefer game state over name in buddysorting. this b/a change in buddy attribute object is willingly due to buddy numberings from 0 (nobuddy game) to 1 (buddy in observer game), 2 (buddy in game playing), 3 (user playing in game for easier finding when dropped from game). so highest is priorized

String() is more explicit than adding an empty string to a number in order to convert it