[coldtea]

I doubt the GitHub thread was "a long poem, typically one derived from ancient oral tradition, narrating the deeds and adventures of heroic or legendary figures or the past history of a nation"

[Tade0]

You're confusing a noun with an adjective.

As an adjective it's something that's "extending beyond the usual or ordinary especially in size or scope".

[matt4077]

The adjective is obviously. derived from the noun, and as such had much of the same meaning originally: "relating to or characteristic of an epic or epics: our national epic poem Beowulf."

And no, I'm not proud of having to weigh in on this subject.

[coldtea]

epic, adjective

  1. relating to or characteristic of an epic or epics.

  2. heroic or grand in scale or character.
  "his epic journey around the world"
  

You were saying?

[Tade0]

Citation needed.

Here's my source: https://www.merriam-webster.com/dictionary/epic

[coldtea]

Mine was OS X dictionary IIRC, but here's dictionary.com:

adjective, Also, epical 1. noting or pertaining to a long poetic composition, usually centered upon a hero, in which a series of great achievements or events is narrated in elevated style: Homer'sIliad is an epic poem. 2. resembling or suggesting such poetry: an epic novel on the founding of the country. 3. heroic; majestic; impressively great: the epic events of the war. 4. of unusually great size or extent: a crime wave of epic proportions. 5. Slang. spectacular; very impressive; awesome: Their burgers and fries are epic!

So if (4) is what you mean, it's not exactly the first definition for the adjective either.