Connect to any remote machine. Run `M-x eshell RET', then `$ locale'. Output:

LANG=en_GB.UTF-8
LANGUAGE=
LC_CTYPE="C"
LC_NUMERIC="C"
LC_TIME="C"

...

All settings other than `LANG' are reset.

In comparison, when I do the same with Emacs 28:

LANG=en_GB.UTF-8
LANGUAGE=
LC_CTYPE="en_US.utf8"
LC_NUMERIC="en_US.utf8"
LC_TIME="en_US.utf8"

Paul
...