Merge bitcoin/bitcoin#23126: doc: update developer docs for subtree renaming

2b90eae33c0b368cc9b3939be224c36c45abd50d doc: update developer docs for subtree renaming (fanquake)

Pull request description:

  Update the developer docs after the [recent subtree renaming](https://github.com/bitcoin/bitcoin/pull/22646#issuecomment-921154730).

ACKs for top commit:
  hebasto:
    ACK 2b90eae33c0b368cc9b3939be224c36c45abd50d

Tree-SHA512: ed0eec8db888e60595c07f4fad0a506673e4b10345fb2dd6d1a98d785da22bddf1fe8896aa52fd67f5e1688e3c91c6b642739e08646f1b920f50f0d35037d961

2 files changed, 21 insertions, 17 deletions

diff --git a/doc/developer-notes.md b/doc/developer-notes.md
index ffb6632e21..0a5a7066ab 100644
--- a/doc/developer-notes.md
+++ b/doc/developer-notes.md
@@ -963,37 +963,41 @@ Subtrees
 
 Several parts of the repository are subtrees of software maintained elsewhere.
 
-Some of these are maintained by active developers of Bitcoin Core, in which case changes should probably go
-directly upstream without being PRed directly against the project. They will be merged back in the next
-subtree merge.
+Some of these are maintained by active developers of Bitcoin Core, in which case
+changes should go directly upstream without being PRed directly against the project.
+They will be merged back in the next subtree merge.
 
-Others are external projects without a tight relationship with our project. Changes to these should also
-be sent upstream, but bugfixes may also be prudent to PR against Bitcoin Core so that they can be integrated
-quickly. Cosmetic changes should be purely taken upstream.
+Others are external projects without a tight relationship with our project. Changes
+to these should also be sent upstream, but bugfixes may also be prudent to PR against
+a Bitcoin Core subtree, so that they can be integrated quickly. Cosmetic changes
+should be taken upstream.
 
-There is a tool in `test/lint/git-subtree-check.sh` ([instructions](../test/lint#git-subtree-checksh)) to check a subtree directory for consistency with
-its upstream repository.
+There is a tool in `test/lint/git-subtree-check.sh` ([instructions](../test/lint#git-subtree-checksh))
+to check a subtree directory for consistency with its upstream repository.
 
 Current subtrees include:
 
 - src/leveldb
-  - Upstream at https://github.com/google/leveldb ; Maintained by Google, but
-    open important PRs to Core to avoid delay.
+  - Subtree at https://github.com/bitcoin-core/leveldb-subtree ; maintained by Core contributors.
+  - Upstream at https://github.com/google/leveldb ; maintained by Google. Open
+    important PRs to the subtree to avoid delay.
   - **Note**: Follow the instructions in [Upgrading LevelDB](#upgrading-leveldb) when
     merging upstream changes to the LevelDB subtree.
 
 - src/crc32c
   - Used by leveldb for hardware acceleration of CRC32C checksums for data integrity.
-  - Upstream at https://github.com/google/crc32c ; Maintained by Google.
+  - Subtree at https://github.com/bitcoin-core/crc32c-subtree ; maintained by Core contributors.
+  - Upstream at https://github.com/google/crc32c ; maintained by Google.
 
 - src/secp256k1
-  - Upstream at https://github.com/bitcoin-core/secp256k1/ ; actively maintained by Core contributors.
+  - Upstream at https://github.com/bitcoin-core/secp256k1/ ; maintained by Core contributors.
 
 - src/crypto/ctaes
-  - Upstream at https://github.com/bitcoin-core/ctaes ; actively maintained by Core contributors.
+  - Upstream at https://github.com/bitcoin-core/ctaes ; maintained by Core contributors.
 
 - src/univalue
-  - Upstream at https://github.com/bitcoin-core/univalue ; actively maintained by Core contributors, deviates from upstream https://github.com/jgarzik/univalue
+  - Subtree at https://github.com/bitcoin-core/univalue-subtree ; maintained by Core contributors.
+  - Deviates from upstream https://github.com/jgarzik/univalue.
 
 Upgrading LevelDB
 ---------------------
diff --git a/test/lint/README.md b/test/lint/README.md
index 7e06308347..c4d76eac94 100644
--- a/test/lint/README.md
+++ b/test/lint/README.md
@@ -27,10 +27,10 @@ Usage: test/lint/git-subtree-check.sh [-r] DIR [COMMIT]
 To do a full check with `-r`, make sure that you have fetched the upstream repository branch in which the subtree is
 maintained:
 * for `src/secp256k1`: https://github.com/bitcoin-core/secp256k1.git (branch master)
-* for `src/leveldb`: https://github.com/bitcoin-core/leveldb.git (branch bitcoin-fork)
-* for `src/univalue`: https://github.com/bitcoin-core/univalue.git (branch master)
+* for `src/leveldb`: https://github.com/bitcoin-core/leveldb-subtree.git (branch bitcoin-fork)
+* for `src/univalue`: https://github.com/bitcoin-core/univalue-subtree.git (branch master)
 * for `src/crypto/ctaes`: https://github.com/bitcoin-core/ctaes.git (branch master)
-* for `src/crc32c`: https://github.com/google/crc32c.git (branch master)
+* for `src/crc32c`: https://github.com/bitcoin-core/crc32c-subtree.git (branch bitcoin-fork)
 
 To do so, add the upstream repository as remote: