Add verbose logs mention to CONTRIBUTING.md (#6703)

docs/CONTRIBUTING.md

@@ -107,6 +107,26 @@ reproduce it, the faster we can fix the bug! It's also helpful to have the
 output of `enso --version`, as that will let us know if the bug is Operating
 System or Architecture specific.
 
+### Turning on verbose logs
+
+Sometimes, it is helpful to attach a verbose log to your bug report. The way to
+enable verbose logging depends on which version of Enso you are using. For a
+standalone distribution (`.exe` on Windows, `.AppImage` on Linux), you can
+enable verbose logging by passing `-debug.verbose` option. If you are starting
+the `project-manager`, or language server separately, then pass
+`--log-level trace` option. With verbose logging, there are a lot of messages
+printed to the standard output, and it is possible that on slower terminal
+emulators this will clog the terminal and hence the whole backend. To avoid
+this, we recommend redirecting the output to `/dev/null`, via a command like
+`enso -debug.verbose > /dev/null 2>&1`.
+
+The logs are kept in a central location `$ENSO_DATA_DIRECTORY/log` - on Linux,
+they are in `$XDG_DATA_HOME/enso/log` (usually `~/.local/share/enso/log`), and
+on Windows they are in `%APPDATA%\enso\log`, see
+[distribution.md](distribution/distribution.md) for details. The log level name
+consists of the timestamp of the log file creation. There is no automatic log
+rotation, so you may want to delete the old logs from time to time.
+
 ## Hacking on Enso
 
 This will get you up and running for Enso development, with only a minimal