The quitter extension (tools/quitter) that we use in various builds (PGO, Valgrind, ...) needs to be signed and the signed xpi checked in whenever its code changes. The procedure for signing it is in https://mana.mozilla.org/wiki/display/FIREFOX/Internal+Extension+Signing, and we need someone to own the code and have permissions to sign the extension. See also bug 1393449 which would remove this extension altogether.

Peter, what timeframe does the extension need to be signed by? I'm trying to determine if it makes sense it sign it versus do the couple of days work to remove the extension.

I got the extension signed for my changes in bug 888600, so I don't particularly care about this. But every time someone else touches the code they'll need to have it signed too. It doesn't look like it happens often (months go by without it being touched), so doing the removal instead sounds fine to me.