Electrum ABC 5.2.10

• Don't change the master private key every time the Avalanche proof editor is opened. This improves the automatic key detection when loading an Avalanche proof by making it less likely that the proof's key is beyond the gap limit for key detection (D14804).
• Fix automatic private key detection when building multi-level Avalanche delegations in a wallet that owns the key for the previous level (D14802).
• Fix an integer overflow when displaying the total amount of stakes in an Avalanche proof (D14781).
• Fix transaction signing in CashFusion, broken in 5.2.8 and 5.2.9 (D14795, D14810).
• Fix miscellaneous bugs and improve test coverage for RPC commands (D14780).
• Electron Cash backports:
  • Speed up loading of very large wallets and misc performance improvements (D14703, D14785)