from the main QMO page (https://quality.mozilla.org/), I clicked on "What is QA?" in the Getting Started box on the right. It led to https://quality.mozilla.org/docs/misc/what-is-qa/, which says: "Sorry, we couldn’t find that We looked everywhere, but we couldn’t find the page or file you were looking for. A few possible explanations: You may have followed an out-dated link or bookmark. If you entered the address by hand, you might have mistyped it. Maybe you found a bug. Good work!"