Obscure

/äb-skyu̇r/

adj. Used in an exaggeration of its normal meaning, to imply total incomprehensibility.

"The reason for that last crash is obscure."

"The 'find(1)' command's syntax is obscure!"

The phrase moderately obscure implies that it could be figured out but probably isn't worth the trouble. The construction obscure in the extreme is the preferred emphatic form.