Why do some properties default to groups?

[Haroenv]

If I run new URLPattern('https://example.com').exec('https://example.com'), I get the output:

{
    "hash": {
        "groups": {
            "0": ""
        },
        "input": ""
    },
    "hostname": {
        "groups": {},
        "input": "example.com"
    },
    "inputs": [
        "https://example.com"
    ],
    "password": {
        "groups": {
            "0": ""
        },
        "input": ""
    },
    "pathname": {
        "groups": {
            "0": "/"
        },
        "input": "/"
    },
    "port": {
        "groups": {},
        "input": ""
    },
    "protocol": {
        "groups": {},
        "input": "https"
    },
    "search": {
        "groups": {
            "0": ""
        },
        "input": ""
    },
    "username": {
        "groups": {
            "0": ""
        },
        "input": ""
    }
}

Why do the hash, password, pathname, search and username have groups set even though the input did not explicitly ask for them? Is that because the input pattern doesn't include those paths and they are considered wildcard automatically?