I drafted some documentation for a new feature in Confluence Cloud to make it easier for people to access and comment.
Today I imported it to Paligo and was impressed by how little cleanup is required. There's a bug with images in HTML5 but I expect they'll fix that quickly. Some special characters in Monospace text were de-escaped, but Preformatted blocks seem fine.
In Confluence, go to Space Tools > Content Tools > Export and export as HTML. Extract the .zip file, delete any extraneous HTML files (Paligo wants only one), and zip the folder. Import the new .zip file.