Is this belie definition 2, "To tell lies about, esp. to calumniate by false statements", definition 4, "To give a false representation or account of, to misrepresent; to present in a false character", definition 6, "To call (a thing) false practically, to treat it as false by speaking or acting at variance with it; to be false or faithless to", or definition 7, "To show to be false, prove false or mistaken; to falsify (expectations, etc.)"? I don't see how any of those makes sense, given that it's an action by some person being said to belie an attribute of something. (Maybe that would make sense if you were one of the developers and reading the changelog demonstrated that the project's complexity were somehow "false"?)

(OED 1ed. vol. 1 p.782, 806 of 1270 in the PDF)

"belie" can also just mean "to be in contradiction with".

Which I assume was the definition being used. As in, "the simplicity of the changelog is in contradiction with the actual complexity of the project".

In that case, definition 4 should fit the bill. Reading the changelog gives a "false representation" on the complexity of the project.

All of these senses have the meaning, loosely, "to be in contradiction with"; my confusion was how any particular one of them applied, and which one. In a way, senses 4 and 7 are opposites: in one case it's the belier that's false, and in the other sense it's the thing belied.

Thanks for that, yes that is indeed the way I am using the word. A bit old-school perhaps...