[andolanra]

The story, if I recall correctly, is that the programmer Edwin Brady had a previous project that was a proof engine, and lacking a suitable name for it, named after an older British children's cartoon called Ivor the Engine.[^1] When it came time to name a newer project, he decided to name it after another character from the same show: Idris, the little red Welsh dragon. This, incidentally, is why the Idris language's logo is a stylized red wing.

[^1]: Ivor the Proof Engine is here, although apparently not actively updated any more: https://github.com/edwinb/Ivor

[archgoon]

Thank you, I had read the FAQ:

http://docs.idris-lang.org/en/latest/faq/faq.html

but could not infer why a dragon from Ivor the engine had been chosen. That the author had previously written a proof engine makes all the sense now. :)