No, yo're wrong about FF ext manager, a lot of Firefox won't never work with K-Meleon.
And the ones which works have often needed modifications.
More, the one which works directly without crash need for the minimum to write kmm file for menus.
Do you think Firefox FF extension manager can write it alone
But, if you look at the 1.5.0 profile structure, you can see that chrome folder has been added.
I don't know if it works as I haven't test it and I just see it yesterday evening.
Mozilla/5.0 (x11; U; Linux x86_64; fr-FR; rv:38.0) Gecko/20100101 Ubuntu/12.04 K-Meleon/76.0
Mail : alain [dot] aupeix [at] wanadoo [dot] fr
Ubuntu 12.04 - Gramps 3.4.9 - Harbour 3.2.0 - Hwgui 2.20-3 - K-Meleon 76.0 rc