I’ve tried the “Test service” (in Services / Manage Piwik Plugins) of the Github repo - “Okay, the test payload is on its way” appears, but the updated version still doesn’t appear on the Marketplace.
P.S.: The commits to the Github repo aren’t counted under “Activity” on https://plugins.piwik.org/LoginEncrypted any longer either, although they used to be earlier.
I don’t know if I should delete the existing Github service hook and set up an new one, or if that would result in the plugin being recognized as a different one, resulting in its rejection by the Marketplace due to an already existing plugin of the same name. (If that is not the issue here already, for whatever reason.)
Thanks @matt! I wrote to that address, haven’t got a response, but the latest version has automagically appeared on the Marketplace some days later. So, this topic is solved for me.