by Pär Thernström on WordPress.org
Useful loggers for SimpleHistory for developers during development of a site or to maintain a live site.

Enable the loggers you want in Settings » Simple History » Developer loggers.
Bring more loggers to WordPress user history plugin Simple History.
That are useful for developers during development of a site or to maintain a live site.
Please note that this plugin is no longer actively maintained and only receives security fixes.
For an up to date alternative please see the Debug & Monitor add-on which logs WP REST API requests, sent emails, HTTP API requests, and WP cron jobs.
Need advanced WordPress audit logging capabilities? Simple History Premium extends your site monitoring with powerful features:
Enhanced WordPress Activity Logging:
Post to Slack
All your events is posted to a Slack channel of your choice, using an incoming webhook. Yes, with this plugin enabled
there is no need what so ever to ever leave Slack to see what’s happening on your site or the site of your
clients or… well, on any site where you have Simple Histor and this plugin enabled.
WP_Mail-logger
See all mails sent with wp_mail(), no matter what the recipient address is.
changelog
404 logger
View page visits that load the 404 template.
JavaScript error logger
See what JavaScript errors users that visit your site is getting.
SystemLog logger
Log all messages from Simple History to the syslog on the server. With this logger enabled there is no need to use the beautiful GUI of Simple History ;).
HTTP API logger
Log all usage of HTTP calls from functions like wp_remote_post() and wp_remote_get().
You can the URL requested, the arguments posted and the full returned result, including server headers.
The time for the request to complete is also logged. Great for debugging!