What is the convention for naming routes?
By design, the route name should NOT mirror the path.  You want to be able to change the path without breaking the route name, which is why other code in the system should refer to the route name only, not the path.  Having a route name that maps directly to the path is akin to a CSS class named .left-align-blue :-)

Some of these conventions are still shaking out.  However, for the typical case the recommended pattern is $module_name.$something_meaningful.  So in your mymodule module, you'd have routes like:

mymodule.settings
mymodule.advanced_settings
mymodule.status_page


And so on.  Note those tell you little about the path.  That's by design, as above.

For entities it's a little bit trickier since core has the advantage that most entities are the same name as the module.  Contrib doesn't always have that.  I would recommend either $entityname.$operation or $module_name.$entityname_$operation.  (I don't think core has any double-period route names at present, but I could be wrong.)

So if I were writing a module with a new entity called "nerd" (it's a candy site), I'd have:

nerd.view (for the page that lets you view a nerd)
nerd.edit (for the edit page)
nerd.delete (for the delete confirmation page)


And so on.  Make sense?