> Because Firefox's "powerful extension model" basically constituted direct access to its internals, which prevented the Firefox developers from making the arch

> Because Firefox's "powerful extension model" basically constituted direct access to its internals, which prevented the Firefox developers from making the architectural improvements that were so sorely needed to make it performant. Not necessarily. They could have added and recommended stable APIs that solve most use cases while still allowing extension developers direct access to the internals at the cost of having to update the extension more frequently.