I'm not sure there's that much documentation on that (and I've rebound those keys personally), but I believe it's spacemacs' integration of
auto-highlight-symbol.el, which is in various files, including
spacemacs/layers/+spacemacs/spacemacs-navigation/funcs.el. You can find out a bit by reading those files. The little key summary there probably indicates spacemacs has defined a
hydra to implement this, though I'm not actually sure where that's defined.
You can see from those filenames that the integration is provided by layer
spacemacs-navigation, for which you'd be able to find docs using
SPC h l spacemacs-navigation RET -- but that's just a stub "TODO" file at the time of writing.
;; A minor mode for emacs.
;; * automatic highlighting current symbol like eclipse IDE.
;; * cycle through highlighted locations.
;; * can specify the range to highlight.
;; * can edit the highlighted symbols at a time.
I found that out by opening the
spacemacs directory in dired, then searching for the string you mentioned using
SPC /, then
SPC h d f auto-highlight-symbol RET and clicking on the link to visit that file.
I believe "iedit" is a multi-line editing package, so presumably that will start a multi-line editing session on the current matches? Why not try the keys and see what they do?