Vim-style browser extensions treat a focused <canvas> like any other page and
intercept hjkl, f, x, and friends. Page-level preventDefault doesn’t
help — content scripts see events first. Exclusion lists need per-player config
and break on itch CDN iframe domains.
trapKeys(canvas) is the tested folk fix: make the focused element look
editable so extensions enter insert-mode passthrough. Used in EndWise and
CELLAGA — Vimium, Vimium C, Surfingkeys, Tridactyl, zero config.