brew extract fails on last working llvm

[Blaisorblade]

I tried to use brew extract to work around https://discourse.brew.sh/t/llvm-config-10-0-1-advertise-libxml2-tbd-as-system-libs/8593/15, and I get a request to file a bug report (but I can't file it, as I don't fulfill the prerequisites):

$ time brew extract --version 10.0.0_3 llvm blaisorblade/personal
==> Searching repository history
Error: llvm: Calling 'devel' blocks in formulae is disabled! Use 'head' blocks or @-versioned formulae instead.
Please report this issue to the homebrew/core tap (not Homebrew/brew or Homebrew/core), or even better, submit a PR to fix it:
  /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Formula/llvm.rb:82


real	0m32.793s
user	0m24.437s
sys	0m7.017s

However, I cannot find a devel block at line 82, of either the latest release or of the latest 10.0.0_3 version (checked with git show 96544f60a9eeb7328877f1a937647c1814f87a8d:Formula/llvm.rb).