varchar (no 'N') vs. text

Let's say I have a database with two tables, a and b.
Each has one column. 'a' has a column 't' of type text. 'b' has a
column 'v' of type 'varchar' (no length specified).
If I join the two tables, I see in the plan something that looks like this:

Merge Cond: (a.t = (b.v)::text)

I thought 'character varying' (aka varchar) sans length was an alias
for text. Is it not?

--
Jon