Comment by candu

Well - that might be overstating the matter; after all, academia also has workshops focused on very small niches...

...but also: it's not uncommon to find industry conferences about a specific framework, because it's not just about the framework - it's about the uses to which that framework can be put, and about interacting with the community around that framework. Both of those facets permit a lot of variety, especially for foundational tools (e.g. web application frameworks, UI libraries, database platforms, etc.)