So here it is. The code is based almost completely on that of the WK Fake Numbers script.
It’s my first time making a script, so… yeah… humble beginnings…
Effect: replaces lessons, reviews, next hour and next day numbers by 0: “none”; <42: “light”; <200: “medium”; >=200: “heavy”
Grease monkey link: https://greasyfork.org/en/scripts/38029-wanikani-number-clobber/code
Ver 1.2: Extension: works also on the lesson and review pages. Can be toggled manually but setting the variable clobberall in the script (true clobbers all, false only clobbers the dashboard). Also thanks to @The1AndMany
Ver 1.1: bug fix: works correctly on the dashboard when accessing through the root of the WK site. Thanks @The1AndMany
Ver 1.0: initial release