gnus-group-jump-to-group-prompt

gnus-group-jump-to-group-prompt is a variable defined in `gnus-group.el'.
Its value is

nil

Documentation:
Default prompt for `gnus-group-jump-to-group'.

If non-nil, the value should be a string or an alist. If it is a string,
e.g. "nnml:", in which case `gnus-group-jump-to-group' offers "Group:
nnml:" in the minibuffer prompt.

If it is an alist, it must consist of (NUMBER . PROMPT) pairs, for example:
((1 . "") (2 . "nnfolder+archive:")). The element with number 0 is
used when no prefix argument is given to `gnus-group-jump-to-group'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.