I have no idea what leaf miner it is, probably Agromyzidae mine? On Symphytum sp. 11.09.2021 Uppsala, Sweden.
Thank you in advance for any help in identification,
Adam
Thank you very much. I belived that it was Symphytum sp. It was Symphutum specimens nearby, by this plant had no flowers. It may be Rumex sp. I suggest that we can leave mines as undetermined as the host plant is uncertain.