Good question, Elin. According to Wikipedia this monument was raised by another wife of Harald "Blue Tooth", king of Denmark , Tove Mistivojsdatter and/or her duplicate, Tove Mistivojsdatter , in memory of her apparently unknown mother, N.N. .
Tove's father is given as Mistiwoj, of the Obodrites . Her mother's name is not identified in the Wikipedia article, which seems a little odd to me since she is the subject of the monument which is documented.
The image somehow mistakenly became attached to Gunhild in 2018.
https://en.wikipedia.org/wiki/Mstivoj
https://en.wikipedia.org/wiki/Tove_of_the_Obotrites
The text on the stone:
"tufa : lRt : kaurua : kubl : mistiuis : tutiR : uft : muþur : sina : kuna : harats : hins : kuþa : kurms : sunaR"
Transkribed: "Tōfa lēt gørva kumbl, Mistivis dōttiR, øft mōður sīna, kona Hara[l]ds hins gōða, Gōrms sonaR."
Danish: "Tove, Mistivis datter, Harald den Godes, Gorms søns kone, lod gøre kuml efter sin mor."
English: "Tófa, Mistivir's daughter, wife of Haraldr the good, Gormr's son, had the monument made in memory of her mother."
My sources: Danish and English wikipedia.