>> >>> This looks nice (I actually have something similar in my
>> >>> `mode-line-format` already), but I think that modifying
>> >>> `mode-line-format` when project.el is loaded is a bit problematic.
>> >>> Perhaps a better alternative would be to define a variable that holds
>> >>> this mode-line construct, along with an autoloaded function that people
>> >>> can call from their init files to actually add this construct to
>> >>> `mode-line-format`.  WDYT?
>> >> In bug#63469 I implemented 'project-mode' with the buffer-local
>> >> variable 'project-name'.  But due to objections I rewrote this
>> >> to simpler and direct implementation.  I could revive the previous
>> >> patch now.
>> >
>> > Could you make it a user option 'project-show-in-mode-line' or similar?
>> >
>> > Minor mode 'project-mode-line-mode' would also be okay.
>>
>> But there is no such mode for vc-mode (vc-mode is not a proper mode).
>
> I indeed think that an optional variable to control the mode-line
> additions would be better than a minor mode: this is too little
> functionality to justify a minor mode.

Ok, here is the implementation with an optional variable: