I don't see a reference to Mozilla's X-Tags. X-Tags already links to listings of web components so why is this so different than that listing but also similar?
Compare it for yourself:
Brick Flipbox: https://github.com/mozbrick/brick-flipbox/blob/master/src/br....
vs
X-Tag Flipbox: https://github.com/x-tag/flipbox/blob/master/src/flipbox.js
-----
Brick Deck: https://github.com/mozbrick/brick-deck/blob/master/src/deck..... AND https://github.com/mozbrick/brick-deck/blob/master/src/card.....
vs
X-Tag Deck: https://github.com/x-tag/deck/blob/master/src/deck.js
A big part of their switch seems to be a result of interpersonal issues with the X-Tag creators. After I left on less-than-good-terms with a handful of folks at Mozilla, they decided to ditch a library that makes components small, modular, and DRY, for what appears to be spite. The new Brick code base is over 2x heavier (despite being billed as a "lightening" move), each component is 40-60% larger (with a ton of repetition and use of X-Tag code), and the browser compat range has been reduced greatly.
They never reached out to the X-Tag team before posting this - it contains glaring inaccuracies and negative sentiment toward X-Tag.
I'm deeply disappointed by their poor open source behavior, and general lack of courtesy.