The lastest PR replaced jQuery-based JSON viewer in favor of HTML Custom Elements based one.
This will break debug viewer on more or less old browsers, so if have to debug something in IE / Edge <= 18 / Firefox <= 63 / Chrome <= 54, most likely you'll have to switch off debug viewer beforehand, debug and turn it on afterwards.
So, it's better to decide and document, which browsers are supported and which will give you more pain in the neck.
The lastest PR replaced jQuery-based JSON viewer in favor of HTML Custom Elements based one. This will break debug viewer on more or less old browsers, so if have to debug something in IE / Edge <= 18 / Firefox <= 63 / Chrome <= 54, most likely you'll have to switch off debug viewer beforehand, debug and turn it on afterwards.
So, it's better to decide and document, which browsers are supported and which will give you more pain in the neck.
Additional info