Can't sync or download decks from ankihub

[abdo.nh]

@jan

Oh @abdo.nh please mind the potential OverflowError your snippet produces (in case you want to push that to the addon)

Someone hit that error already: Specific Deck can not be downloaded - #4 by papenbro

We won’t increase the field length limit for now (I thought the deck had a legitimate need for huge fields).