From #3047 (comment):
Aaaaaaaaaaah! It seems in our rebasing we missed parts of 8ab980b.
fish_mode_prompt in 2.3.0 still checks $__fish_vi_mode, but the functions don't set it anymore. The easiest workaround is probably set -g __fish_vi_mode 1.
In case we do a stable release based on the Integration_2.3.0 branch that one should definitely be included. If it's instead based on master this is already fixed.
For 2.3.1 release:
Yikes. Let's do a 2.3.1 release with this and anything else that we find.
This makes fish_mode_prompt rely on $fish_key_bindings instead.
fish_bind_mode is also set in default mode (only always "default"), so
it can't be used as the indicator.
(cherry picked from commit 8ab980b)
Cherry-picked as fcbeddc.
Ignore fish-shell preset vi mode indicator
Was caused by fish-shell/fish-shell#3067