There is a new, cross-browser standard for developing extensions in Firefox. You'll need to update your legacy extensions to stay compatible.
Jo něnto nowy standard za wuwijanje dodankow w Firefox, kótaryž dajo se za wšake wobglědowaki wužywaś. Musyśo swóje stare dodanki aktualizěrowaś, aby kompatibelne wóstali.