> What does this one differently that the other thirteen in a dozen don't?

Mozilla's a lot more trustworthy with privacy and data, and they're unlikely to sell the project to someone who only wants to stuff it full of malware/adware/crypto stuff - or do it themselves.

Are they allowed to reuse Thunderbolt when it's already taken in the same industry?

...and also differs in just three characters from another Mozilla product.

"I'm using Mozilla Thunderbolt."

"Huh, do you mean Thunderbird?"

"No, Thunderbolt!"