In bug 1660706, I am adding a test to check when various modules are loaded - to ensure they are not loaded earlier than necessary.

At the moment, these core modules are being loaded before first paint:

resource://gre/modules/PlacesUtils.jsm
resource://gre/modules/Promise.jsm
resource://gre/modules/Preferences.jsm
resource://gre/modules/Sqlite.jsm

They are probably unnecessary, and we should investigate delaying them until necessary (this will likely need to be split up into multiple bugs once the initial investigation is done).

How can one check which are loaded before first paint?

(In reply to Magnus Melin [:mkmelin] from comment #1)

How can one check which are loaded before first paint?

See the first patch on bug 1660706 (that needs review still :) )

The test has a deny list at the moment, but if you run the test, it'll also print out all the modules / services that get loaded.

assuming this goes back to at least v68. please change if that is not correct