While we have started working on it, there won’t be any snapshots for Minecraft 1.10 for at least another 2-3 weeks. This snapshot is for Minecraft 1.9.x and will eventually lead to a 1.9.3 pre-release.
TL;DR: this snapshot is for 1.9.x and not for 1.10
Notable changes:
Introduces some new bugs
Fixed some existing bugs
Removed the new bugs again
Bugs fixed in 16w15a:
[Bug MC-94438] - Server: Massive Lag in any versions 15w49a and later
Wait a moment… I think I have a deja vu here. Didn’t we have exactly the same blog post last week?
Please report any and all bugs you find in Minecraft to bugs.mojang.com. If nobody reports a bug, we can’t fix it!
To get snapshots, open your launcher and press the “New Profile” button. Call it “snapshots” and check the box saying “Enable experimental development snapshots” and save. To switch to the normal version, you can select it in the dropdown at the bottom left corner of the launcher. Back up your world first or run the game on in a different folder (See the “new profile” dialog).
Snapshots can corrupt your world, please backup and/or run them in a different folder from your main worlds.