Source code is awkward to share outside of a code editor. Email clients mangle it. Screenshots aren't searchable. Word processors strip the formatting. The simplest portable format is still a PDF, and the simplest way to make a good code PDF is to point a tool at your project folder and let it do the layout for you.
PDFy is that tool. It runs entirely in your browser, reads your folder using the File System Access API, and produces a single searchable PDF: real text with syntax highlighting, paginated so long lines don't break, with a cover page and table of contents if you want them.
The sections below cover who reaches for PDFy, what makes the output worth using, and the questions people ask before they try it.