[bombastry]

The two blues are identical: the CSS has them both colored as "dodgerblue."

Facebook appears to be the only one in the "Proprietary" category. The rest of the blue ones are all "Chrome."

[crazypython]

It's a joke that if an API is Chrome-only, it might as well be proprietary.

Chrome-only (neither supported by Firefox or Safari) APIs typically have less concern for privacy and security. For example, Web MIDI lets a web browser install arbitrary binary executables on MIDI devices.