I create backup and get name base.backup. Create another copy and get name base.sql.
What's the difference in backup formats .sql - .backup then using pgadmin?
I would be grateful if there is a link to the source. Thanks.
You can name your files whatever you want. PgAdmin4 does not force you to use specific extensions for specific formats. It would be sensible to use *.sql for plain-format and *.backup for custom format, but pgAdmin4 does nothing to enforce (or even effectively encourage) this.