What does "ptr" stand for in Django ORM column names?

Question

With these Django ORM models:

class A(Model):
    pass

class B(A):
    pass

The table for B in the resulting schema contains the field:

"a_ptr_id" integer PRIMARY KEY

Just for the sake of better understanding Django's design choices - It there any rationale documentation that mentions what "ptr" signifies?

My only guess is that it's an abbreviation for "pointer", but that seems pretty dumb since essentially any field with a foreign key constraint conceptually resembles a pointer.

Answer 1

It does stand for "pointer", but it's only used specifically for model inheritance in order to point to the parent model. Normal FKs only get "_id".