I spent 10 minutes looking for an extension to do this, then found that its, smartly, built into Firefox’s bookmark manager. I’m not sure what this mindset is called, Extension Dependance? Anyway, if you need to move bookmarks from one machine to the other in Firefox:
- From the Bookmarks menu, select Organize Bookmarks.
- Choose Export… in the File menu and save your file.
- On the target machine, after selecting Organize Bookmarks, select Import… and choose the file you created in step 2.