Quill
a what-you-see-is-what-you-need editor with clean display of your content and subtle presentation of semantic markup. It also has live preview and navigation support, though those are supportive; the real point is that it's an editor.
Parchment
a simple but powerful rendering back-end which takes these documents and outputs them as PDF files. Different document types have different rendering engines (ie, stylesheets) customized for the purpose.
Commercial Use
Modify
Distribute
Place Warranty
Sub-License
Hold Liable
Distribute Original
Disclose Source
Include Copyright
State Changes
Include License
These details are provided for information only. No information here is legal advice and should not be used as such.