Back in July 2022, French climber Seb Bouin made the first ascent of a new 130m route through the steep roof of Hanshelleren Cave in Flatanger, Norway. The new line linked existing routes Nordic Plumber 8c and the second pitch of Thor's Hammer 9a+ and then up the final headwall to the summit of the cave. Seb linked the full line and climbed it in a single 130m pitch, giving it an overall grade of 9b/+ and naming it Nordic Marathon.
I'm surprised no one has commented on using a slack fixed sling off a single bolt to 'safeguard' untying and retying the rope, though. Rather him than me !