This weekend Twitter/X rolled out age-restriction on adult content posts for Australian users. This is not required by the Australian social media laws (which instead entirely ban under-16s from platforms) and may be an indication they plan to rollout this feature globally, as Discord planned after doing the same in December when likewise not required to.
On one hand, Twitter is happy to auto-verify certain accounts based on account or email age. On the other hand, Twitter's age verification only functions within the X mobile app, and anyone on desktop/browser can go fuck themselves.*
*Unless you head to an account's Media tab, in which everything is uncensored.