In case you care about accessibility — usability through assistive technologies, enabling the use of websites to people with various disabilities, here’s a short list of tools that can be of great help.
They will also shed some light on all those aria- attributes that you may have seen in bootstrap code.
Besides the lighthouse checker now externalised from chromium, there’s also:
- tota11y: https://khan.github.io/tota11y/
- tenon (VERY detailed): https://tenon.io
- http://wave.webaim.org/
- http://cynthiasays.com/ (looks like it requires feeding an email)