I think "showing daylight" is a metaphor for there being space between two things or ideas. So in a sense her and Biden's views on Israel are not conjoined, hence "daylight" can be seen between them, like slats in a fence.
This makes sense thanks for the explanation 🙏 - also realised that the phrasing of the headline tripped me up. It says Harris shows daylight ‘with’ Biden which i think is completely the wrong word to use there, but i suppose they had written themselves into a corner by insisting on starting the sentence with ‘Harris’
I feel like they’ve butchered it as well - surely this phrase needs to take the form of ‘daylight’ (or not) between x and y? Use of ‘with’ tripped me up - daylight with Biden? I guess they meant that Harris skipping the address ‘showed daylight’ between her and Biden on this issue, but i would give them an F for phrasing tbh. Complete trainwreck if you ask me.
They didn't ask what the article was about, they asked what that specific (somewhat uncommon) term meant. Maybe they're young, maybe they have a disability, maybe this is a 2nd language for them, etc...