As is, the change looks good. But please look into out-of-order backports in these files that will likely be a headache for others:

• rpc_psbt.py
• wallet_avoidreuse.py
• wallet_keypool_topup.py

Looks like other parts of the stack take care of it.

In the future, we need to make this notice deactivate on its own once the date has past. That will decouple the code cleanup from requiring a new deployment to remove the notice.

clang-format -> clang-format-8

Add missing php-codesniffer

Missing backport of p2p_dos_header_tree.py

Figure out what's up with the build-without-wallet failure

size_t

Use swap to emulate std::move for C++98

Introduce preprocessor directive to allow compilation with std::move. This change differs from
the upstream PR for now, as a strategy for C++11 in UniValue will take more time.

Since we own the seeder code now, consider new class names to not include the C... prefix. It's not useful.

Looks fine, but please investigate why the linter was not applied to the imports.