Hi,
My fix for SceneLoader.ImportAnimations got merged 2 days ago (Added "pluginExtension" to SceneLoader.ImportAnimations by phenry20 · Pull Request #8413 · BabylonJS/Babylon.js · GitHub), but I checked the latest package version on npm and noticed that the latest package was published 12 days ago. Is there are place to get the nightlies from packages from npm? If not, how often are nightlies published?
It varies. Sometimes a few days, sometimes 2 weeks. I believe @sebavan wanted to release one today or tomorrow, but I will let him confirm
We are mostly trying to have a weekly or fortnightly cadence and increase the frequency as we get closer to the release. I will deploy a nightly tonight.
Alright. Thanks for the swift reply! Have a great day 
nw publishing as we speak so it will be up in about 30 minutes for 4.2.0-alpha.21