The stylized treatment of "MIDI" (the logo) is owned by the MMA and may be used only as defined by MMA. Typically we use that to identify products that comply with certain MMA specifications. More information about MMA trademark policies can be found here: https://www.midi.org/mma-trademark-policies
We have considered a "Web-MIDI" logo, and have had discussions about the idea with W3C, but no decision has yet been made. So the design that you refer to is not approved for use by MMA.
The situation may change in the future (when the Web-MIDI API is adopted by W3C).