import { guitabtooltip } from "https://deno.land/x/denops_std@v3.10.1/option/mod.ts";
{only available when compiled with GUI enabled} When nonempty describes the text to use in a tooltip for the GUI tab pages line. When empty Vim will use a default tooltip. This option is otherwise just like 'guitablabel' above. You can include a line break. Simplest method is to use |:let|: > :let &guitabtooltip = "line one\nline two" <