RSG (Ryan Specialty Group) recently announced a rename to Ryan Specialty (no
"Group"), but I'm not sure if the legal name has been changed yet or not, so
I'll wait on that.
This largely reintroduces the legacy classification system, but there are a
number of things that are not affected by the flag. For example:
1. Alias classifications are still optimized when the flag is off;
2. Classifications without predicates emit slightly different code than
before, though their functionality has not changed;
3. There's been a lot of refactoring and minor optimizations that are
unaffected by the flag;
4. lv:match/@pattern will now emit a warning; and
5. Cleaning and casting of input data is not gated.
This allows us to incrementally migrate to the new system where behavior may
be different, but this is admittedly a bit dangerous in that the new system
was aggressively tested and reasoned about, so reintroducing the legacy
system may combine in unexpected ways.