I haven't upgraded or installed new plugins for a while now, but the install.log keeps getting the following messages.
2019-06-10 16:33:03...installerHook: Could not find custom/install/install_hooks.php
2019-07-01 23:24:12...installerHook: Could not find custom/install/install_hooks.php
2019-07-10 10:18:59...installerHook: Could not find custom/install/install_hooks.php
2019-08-06 10:38:50...installerHook: Could not find custom/install/install_hooks.php
2019-08-08 10:36:18...installerHook: Could not find custom/install/install_hooks.php
2019-10-11 05:58:43...installerHook: Could not find custom/install/install_hooks.php
2019-10-12 03:23:55...installerHook: Could not find custom/install/install_hooks.php
2019-11-09 13:20:48...installerHook: Could not find custom/install/install_hooks.php
2019-11-17 02:05:39...installerHook: Could not find custom/install/install_hooks.php
2019-12-06 22:35:16...installerHook: Could not find custom/install/install_hooks.php
2019-12-12 03:28:22...installerHook: Could not find custom/install/install_hooks.php
2020-01-06 01:18:01...installerHook: Could not find custom/install/install_hooks.php
2020-01-14 20:39:39...installerHook: Could not find custom/install/install_hooks.php
2020-02-03 11:51:19...installerHook: Could not find custom/install/install_hooks.php
2020-02-14 01:42:43...installerHook: Could not find custom/install/install_hooks.php
2020-03-06 06:21:25...installerHook: Could not find custom/install/install_hooks.php
