We will start by making the case that the capabilities "commit to the transaction spending this output" and "verify a BIP340 signature for an arbitrary message" are a good stopping point for a Bitcoin soft fork.
He explains what these capabilities compose into and covers alternative sets of capabilities provided by other potential forks. This thread is meant to just discuss soft fork capabilities of CTV+CSFS and alternatives - what the capabilities are and why we might want them. Poinsot implies he'll follow up with other discussions for "demonstration of usage" and "design of the operations to achieve these capabilities."
Footnotes