So RSA 260 is about 2-3 times harder than RSA 250, which was solved in 2700 core hours in 2020, so it’s probably no algorithmic improvements, just a tweak here and there plus faster hardware.
For reference, check this out:
> cuda-sieve is an experimental, standalone CUDA implementation of the lattice-sieving relation-collection pipeline used by the Number Field Sieve. It builds factor bases, sieves both sides of a special-q lattice, performs trial division and GPU cofactorisation, and emits relations for msieve.