What is the meaning of abstract method access modifiers in abstract classes?

Question

PHP

abstract class AbstractQueryFilter {

    abstract protected static function fromHttpRequest(Request $request): self;

final class AnimeSeasonFilter  extends AbstractQueryFilter {
    public ?int    $sequence;

    public static function fromHttpRequest(Request $request): self {
        return (new self($request))
            ->setSequence($request->get('sequence'))
            ;
    }

abstract classes cannot be initialized, only inherited.
Therefore, is there a private method or a protected one? After all access all the same defines child class.

Answer 1

Such a class has two interfaces, one public for clients, and the second for heirs, i.e. tells them what to do.