Context

This is the part of !2671 (merged) that can be merged right away, before actually doing the OCaml upgrade.

Manually testing the MR

The changes are relatively simple, and should not change the semantics of the code. If the CI is green, I think we are good to go.

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
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