Bitcoin Developers debated making Graftroot, a cryptographic signing scheme, optional or removing it altogether. The discussion began with Pieter Wuille via Bitcoin dev:

Given the recent discussions about Taproot and Graftroot, I was wondering if a practical deployment needs a way to explicitly enable or disable the Graftroot spending path… In theory, it seems that this shouldn’t be needed: the key owners are always capable of spending the funds anyway, so them choosing to delegate to others shouldn’t enable anything that isn’t possible by the key owners already.