A few interesting tidbits, some still plans, some already in motion (if they interest you, there’s about 4x as many interesting items in the post itself):

• experiments with Git’s xdiff library, and 10x speed improvements to it that are being submitted back upstream
• –dry flags for every command that modifies things
• a curses interface for running revsets
• offering granular –allow (new-head, new-branch, delete-bookmark,…) flags insteads of a ‘damn the torpedoes’ –force flag that disables every safety stop at once.
• There was talk of establishing a formal “stack” primitive, both as an internal and user-facing concept for expressing “the current commits I’m working on.” Various parts of the internal code already expose a “stack” and “hg show stack” exposes a stack to the user. The end goal would be for various commands to take the current stack into account when deciding how to behave.