Patrice your list loads for me perfectly fine (yet it is only 4.5KB in comparison to 48 of mine, so you have like 10% of extensions listed), Backstaged list also works for me (MMF2 Developer here but in English) I would assume that last patch corrupted the kcqtvr file - try removing it from your Extensions folder.
Also JSON extension should be in System category not Sytem it was a typo sorry for that. Reuploaded the files. I will try to keep both English and French versions updated.
http://tm2fk.pl/exts.zip
http://tm2fk.pl/exts-fr.zip