The documentation page https://docs.moodle.org/dev/Activity_modules#install.xml claims "If your module does not require any new tables then this file is not necessary." This, is not true.
In fact, Moodle requires the existence with the same name as the module. See https://moodle.org/mod/forum/discuss.php?d=316192.

The documentation should be updated to reflect the information in the forum posting.