Hate to be cynical, but I feel like they're just releasing a new one every week just to stay in the news.
I think we have this revisionist history where the signers to the Agile Manifesto invented these processes from whole cloth, when it's more accurate to think of it as 80% curated list of existing practices, >10% discovered, <10% invented.
I ran a Kanban board in 1995, and I wouldn't learn about Deming, Goldratt or Ohno for another ten years. I think a couple people were upset or at least perplexed by my 'yeah ok' reaction to some of their revelations.
The previous one was done on May 5, 2020: https://www.mozilla.org/en-US/firefox/76.0/releasenotes/
And the one before on April 7, 2020: https://www.mozilla.org/en-US/firefox/75.0/releasenotes/
More or less, one release per month. Hardly "every week".