A flange can also be a plate or ring to form a rim at the end of a pipe when fastened to the pipe (for example, a closet flange).
mechanical joint pipe - actually a combination of push-on and flanges
where as a push -on type fitting has an integrated retaining mechanism inside the 'bell' end that locks the spigot end in place.
Saying all that, and given the actual functionality of pipes, one can still not expect to get joint section details from the pipe network...it's more a designation for your reports and labels than the pipes being true models of those respective types of fitments.
