Underscore in ACF custom post type’s fields

Hey, in my agency we are working on a website for an international real estate company.

They approached us because they wanted their website to be fast. The one they have right now is quite slow and is build on top of elementor.

They have a post type named “Properties” for all the proerties they have. The complexity ends there, other than that they just have some contact forms and an embedded AI chat.

Their website also has a lot of plugins, and overall it’s a mess. I like to keep the themes I make very clean.

What’s brothering me about this project is two things:

They wanted speed, so should I install ACF to create the post type? Or should I code the post types and their fields, and their respective validations manually?

Second question, their current properties post type has a lof of them, and some fields are repeated, one with an underscore and one without it. For example, they have a button that looks like this. Im gonna use the notation ACF uses when you export a post type.

“button”: “https://randomlink”,
“_button”: “efb72030”

I don’t understand what the value of _button means and why is it there even. Should I just ignore it?


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