So, Twitter is no longer designated as a "core platform service" (gatekeeper) under the DMA. Twitter's reasoning for this is.... interesting:

"First, X Holdings Corp. argues that X does not constitute an important gateway
for business users to reach end users within the meaning of Article 3(2)(b) of
Regulation (EU) 2022/1925 for the following reasons: (i) X is not part of a
digital/platform ecosystem, (ii) X operates on a small, decreasing scale, and (iii)
X’s relative user engagement is low and declining"

ref. https://ec.europa.eu/competition/digital_markets_act/cases/202441/DMA_100041_631.pdf and https://ec.social-network.europa.eu/@EUCommission/113316593914664643