I'm sorry this add-on is just some links to validators and tools that I already have in my bookmarks. One star is too much really. Uninstalled. PS: the stars rating should include a black star for better evaluation.
This is an excellent add-on. Bringing these essential testing facilities to the toolbar is going to make mobile development a lot easier for a lot of developers.
There's lots of scope for expansion, but I hope you manage to maintain the simplicity of the add-on. Thanks!
The reference links are also useful, but could possibly do with refining as there's some chaff in there and there are a few biggies missing that I'd like to see - e.g., an intelligent (device-specific) link/utility to DeviceAtlas would be great addition to the Reference section.