This helps you create a keyword for part of a site, letting you fill out the rest as part of a 'search'.
For example saving a documentation site with the keyword of vd.
e.g. vd button -> https://vista.design/swan/components/button/
e.g. vd selection-set -> https://vista.design/swan/components/selection-set/
This can be done with anything, e.g. mdn https://support.mozilla.org/en-US/kb/bookmarks-firefox#w_how-to-use-keywords-with-bookmarks
You can do this with any site, just edit the bookmark with a Keyword and use %s in the URL for the replacement string.
Not sure if this is also possible in Chrome.