Vendor homepage https://www.allroundautomations.com/products/pl-sql-developer/
Product help there is no online verson, but release notes https://www.allroundautomations.com/products/pl-sql-developer/release-notes/
Config
-- Data Engineer should be granted these system privileges for some
-- PL/SQL Developer features to work.
grant select on v_$session to my_user;
grant select on v_$sesstat to my_user;
grant select on v_$statname to my_user;