I tried adding this myself but I got an unspecified error message. This is the Spanish Wiktionary to search for Spanish lemmas.

{
    "dictName": "Wiktionary (es)",
    "windowUrl": "https://es.m.wiktionary.org/wiki/<word>#Español",
    "windowUrlMatch": "wiki/([^&]+)",
    "resources": {
        "styles": ["wiktionary.less"]
    }
}