Hi,
I read about naming conventions and the Frankenstyle naming.
But I couldn't find if a plugin name is alowed (discouraged) to contain underscore.
for example my_first_plugin. so the frankenstyle name would be [enrol | auth | ...]_my_first_plugin
Underscores in plugin names will work, but are very much discouraged.
So the plugin should be called mod_myfirstplugin (or enrol_myfirstplugin, etc)
agree with Davo.
The reason for discouraging is the "special" behavior of activity modules - very often they are allowed to use the plugin name without the "mod_" prefix where all other plugin types should use the prefix. Imaging the activity module that is called "mod_enrol_counter" - the shorter name "enrol_counter" may be mistaken for the enrolment plugin.