"If the element is a child of an ol element: value "

[zcorpan]

https://html.spec.whatwg.org/multipage/semantics.html#the-li-element

If the element is a child of an ol element:​ value

This means that the following is invalid

<template><li value=5></template>

which probably should be valid. Validator.nu gives no error for the above, but gives an error for <ul><li value=5></ul>.

Fix:

"If the element is not a child of an ul or menu element: value"