$ opam install ocaml-protoc
The following actions will be performed:
  ∗ install dune         3.6.1 [required by ocaml-protoc]
  ∗ install stdlib-shims 0.3.0 [required by ocaml-protoc]
  ∗ install pbrt         2.3   [required by ocaml-protoc]
  ∗ install ocaml-protoc 2.3
===== ∗ 4 =====
Do you want to continue? [Y/n] Y

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><>  🐫
⬇ retrieved ocaml-protoc.2.3  (https://opam.ocaml.org/cache)
⬇ retrieved stdlib-shims.0.3.0  (https://opam.ocaml.org/cache)
⬇ retrieved pbrt.2.3  (https://opam.ocaml.org/cache)
⬇ retrieved dune.3.6.1  (https://opam.ocaml.org/cache)
∗ installed dune.3.6.1
∗ installed stdlib-shims.0.3.0
∗ installed pbrt.2.3
∗ installed ocaml-protoc.2.3
Done.

<><> pbrt.2.3 installed successfully ><><><><><><><><><><><><><><><><><><><>  🐫
=> Pbrt: runtime library for ocaml-protoc.

   A shim library named "ocaml-protoc" still exists, to ease the
   migration.

<><> ocaml-protoc.2.3 installed successfully ><><><><><><><><><><><><><><><>  🐫
=> The runtime library is now called "pbrt".