Running a script that contains the single line:
redef foo::bar = T;
produces the cryptic message:
internal warning in ./myscript.bro, line 1: Can't document redef of foo::bar, identifier lookup failed
It's not clear what "document" means here nor why this makes sense as an "internal warning".
BTW: in filing this ticket, the interface told me that Bro 2.5.3 is "unreleased".