build, wallet, doc: Remove BDB

doc/files.md

@@ -8,14 +8,14 @@
 
 - [Multi-wallet environment](#multi-wallet-environment)
 
-  - [Berkeley DB database based wallets](#berkeley-db-database-based-wallets)
-
   - [SQLite database based wallets](#sqlite-database-based-wallets)
 
 - [GUI settings](#gui-settings)
 
 - [Legacy subdirectories and files](#legacy-subdirectories-and-files)
 
+  - [Berkeley DB database based wallets](#berkeley-db-database-based-wallets)
+
 - [Notes](#notes)
 
 ## Data directory location
@@ -75,7 +75,7 @@ Subdirectory       | File(s)               | Description
 
 ## Multi-wallet environment
 
-Wallets are Berkeley DB (BDB) or SQLite databases.
+Wallets are SQLite databases.
 
 1. Each user-defined wallet named "wallet_name" resides in the `wallets/wallet_name/` subdirectory.
 
@@ -88,15 +88,6 @@ Wallets are Berkeley DB (BDB) or SQLite databases.
 5. Any copy or backup of the wallet should be done through a `backupwallet` call in order to update and lock the wallet, preventing any file corruption caused by updates during the copy.
 
 
-### Berkeley DB database based wallets
-
-Subdirectory | File(s)           | Description
--------------|-------------------|-------------
-`database/`  | BDB logging files | Part of BDB environment; created at start and deleted on shutdown; a user *must keep it as safe* as personal wallet `wallet.dat`
-`./`         | `db.log`          | BDB error file
-`./`         | `wallet.dat`      | Personal wallet (a BDB database) with keys and transactions
-`./`         | `.walletlock`     | BDB wallet lock file
-
 ### SQLite database based wallets
 
 Subdirectory | File                 | Description
@@ -123,6 +114,15 @@ Path           | Description | Repository notes
 `addr.dat`     | Peer IP address BDB database; replaced by `peers.dat` in [0.7.0](https://github.com/bitcoin/bitcoin/blob/master/doc/release-notes/release-notes-0.7.0.md) | [PR #1198](https://github.com/bitcoin/bitcoin/pull/1198), [`928d3a01`](https://github.com/bitcoin/bitcoin/commit/928d3a011cc66c7f907c4d053f674ea77dc611cc)
 `onion_private_key` | Cached Tor onion service private key for `-listenonion` option. Was used for Tor v2 services; replaced by `onion_v3_private_key` in [0.21.0](https://github.com/bitcoin/bitcoin/blob/master/doc/release-notes/release-notes-0.21.0.md) | [PR #19954](https://github.com/bitcoin/bitcoin/pull/19954)
 
+### Berkeley DB database based wallets
+
+Subdirectory | File(s)           | Description
+-------------|-------------------|-------------
+`database/`  | BDB logging files | Part of BDB environment; created at start and deleted on shutdown; a user *must keep it as safe* as personal wallet `wallet.dat`
+`./`         | `db.log`          | BDB error file
+`./`         | `wallet.dat`      | Personal wallet (a BDB database) with keys and transactions
+`./`         | `.walletlock`     | BDB wallet lock file
+
 ## Notes
 
 <a name="note1">1</a>. The `/` (slash, U+002F) is used as the platform-independent path component separator in this document.