The visitor guidance asks for evidence of the sponsor's legal status in the UK where relevant, such as their visa or settlement status. Appendix V requires that a third-party sponsor is not, and won't be, in breach of immigration laws at the time of the decision.
A British citizen sponsor can show their passport. A sponsor on a work visa, with indefinite leave or settled status under the EU Settlement Scheme, can show the evidence of that status. These documents are in English, so translation isn't involved, but leaving them out leaves an obvious gap.
It's worth the sponsor checking that their own permission covers the period of your visit. A sponsor whose visa expires in the middle of your planned stay isn't in breach yet, but it's a question the caseworker might reasonably ask, and the answer is better in the file than missing from it.