Timestamp field

Am I right in my thinking that Postgres does not have a pseudo timestamp
field that is updated whenever a row is added or updated?   Did it used
to have one before time travel was removed?

If no timestamp field, are there any other pseudo fields that are
updated every time?  I noticed that the 'ctid' field seems to qualify,
but what does something like (1,54) mean?

Thanks for any help.

Byron