I liked this idea at first, but the more I think about it the less I'm sure it works. Intra seems like a word which denotes physical boundaries to be within. It prefixes words like intramural, intramuscular, and intracellular. It's used for intranet as well, and while this usage of the prefix works, it has more broad use-cases than that. On the other hand, internal seems very clear and direct, and might suit a more digital, organizational context with less of a physical or spatial aspect to it.
Also, since intra is typically used as a prefix, it seems strange to use it bare. People familiar with intranets will probably make (or assume) the connection, but others might find it unclear while "internal" would likely not be.
Also, since intra is typically used as a prefix, it seems strange to use it bare. People familiar with intranets will probably make (or assume) the connection, but others might find it unclear while "internal" would likely not be.
Even so, I do prefer .intra for selfish reasons.