explain statements question

We're using PostgreSQL (10.6) as part of a product at work that's
maintained by a third party company. I've been monitoring queries to the
PostgreSQL database using PGAdmin3's server status functionality. Lately,
we've been seeing a lot of queries (via the server status page and or
checking pg_stat_activity) that start with Explain (FORMAT XML, VERBOSE
true). Would explain ever be run because of a PostgreSQL setting or
another SQL statement sent to the database or would we only see this if the
application sent a literal "explain" command in SQL to the database? Am
trying to find out why we are seeing so many explain statements after the
last upgrade and whether they are valid commands or perhaps someone just
left debug statements of some kind in the application.

Also, if someone knows a good replacement tool for the server status page
in PGAdmin3 that will work with later versions of PostgreSQL (such as 12),
would very much appreciate hearing about it.

Thank you.