If you use the feature in Consolation 3, or in the next version of Ulbow, to write a logarchive, please be aware of an important limitation when using macOS 10.15 Catalina. The feature works, but you are likely to find that you can only save the resulting logarchive to folders, such as your Home folder and the folders within it, which are on your startup volume, and not to external storage.
This appears to be a problem generated by Catalina’s privacy protection, but trying to add the app or the
log command to the Full Disk Access list in the Privacy tab of the Security & Preferences pane doesn’t appear to help.
A fuller explanation will appear here in the morning (3 January 2020), and the next beta release of Ulbow will be released early next week, once I have completed its documentation and notarized that version.