What permissions are required for e.g. EXPLAIN UPDATE ...

Hello,

Or put another way, does an EXPLAIN UPDATE on a table really require
UPDATE permissions to run? Why can't it be done without UPDATE
permissions? I can understand EXPLAIN ANALYZE UPDATE requiring it, since
it actually executes the statement, but why would a regular EXPLAIN
UPDATE require it? Is this documented somewhere in standard postgres
docs? The only answer I've been able to find on the internet is "The
user needs all privileges needed for the query that should be explained"
found here: https://stackoverflow.com/q/72984543

What does an EXPLAIN do exactly to require the extra permissions? I've
been searching the postgres documentation and the internet, but haven't
managed to find an answer.

Thanks for any help!

Cheers,
Thomas