[en] кур: wrong headword parsing

[cacfd3a]

кур. Probably thrown off by unexpected characters '[18ᵗʰ c. to mid 19ᵗʰ c.]'

  "forms": [
    {
      "form": "кур m anim [18ᵗʰ c. to mid 19ᵗʰ c.]",
      "tags": [
        "canonical"
      ]
    },

Weirdly... I don't find this era denotation anywhere in the Wikitext and it is also not specified in the head_templates field...?

"head_templates": [
      {
        "name": "ru-noun+",
        "args": {
          "a": "an"
        },
        "expansion": "кур • (kur) m anim (genitive ку́ра, nominative plural ку́ры, genitive plural ку́ров)"
      }
    ]

Edit: it's part of Etymology 2

{{ru-noun+|a=an}} {{lb|ru|mostly with verbs {{m|ru|де́лать|tr=-}} and less often {{m|ru|стро́ить|tr=-}}, and both in the singular and as a|_|pluraletantum}} {{defdate|18<sup>th</sup> c. to mid 19<sup>th</sup> c.}} {{cln|ru|obsolete forms}}

[kristian-clausal]

It's in Etymology 2, it's a defdate template. I'll take a look at it at some point.