Emacs 25 is now on its second pretest release, so now is a great time to play with it. You can check for bugs in core, make sure your favourite packages work, and get a sneak preview of upcoming features!
Emacs is already a self-documenting editor, but 25.1 will include several improvements to discovering how your editor is configured.
C-h k (or
M-x describe-key) is a really handy command for finding
out what command runs when you press a key. Emacs 25 improves on this,
telling you which keymap it found the keybinding in.
If you’ve ever had a major mode or minor mode override your favourite global keybinding, it’s now easy to find the cause.
What if you’ve already typed something and you want to know what
M-x view-lossage will show you the last keys you pressed,
so you can work out what happened. This is much improved in Emacs 25,
where you can directly see which commands were called by each
Emacs 25: now more Emacsy than ever.
If you liked this, Artur Malabarba has a great series on other features upcoming in 25.1.