because you don't want to accidentally edit a reference document a teacher forgot to mark as view-only and have your name appear on the Modified-By List of Shame™ - Userscript

dont-edit-teams-docs.user.js

// ==UserScript==
// @name     Don't Edit Documents from Teams
// @version  1
// @include  https://*.sharepoint.com/*
// @grant    none
// ==/UserScript==

const searchParams = new URLSearchParams(location.search)

if (searchParams.get("wdOrigin") === "TEAMS-ELECTRON.teamsSdk.openFilePreview" && searchParams.get("action") === "edit") {
  searchParams.set("action", "view")
  location.search = searchParams.toString()
}