As for finding them: the nice property of syntax errors is that they are trivial to detect statically��� so e.g. we can add that people never can commit code like that
NOPE.
The problem I had was that NBExternalStructure was changed from a variable bytes class to a normal one. So subclasses were committed without error but still couldn't be loaded with a more recent NB. Errors WILL happen, and fixing those is where plain text beats objects���