The test package
The Portable Docs Lab is a fictional package with a README, an overview in docs/, a decision, a local SVG and a clearly labelled broken-link exercise. It is small enough to inspect by hand. Aero Markdown publishes this folder as a reading example; this article describes file-path behavior, not an application speed or rendering benchmark, and it is not a claim about another app.
Three changes, three different outcomes
First, extract the ZIP and follow the README link to docs/overview.md. That page refers to ../assets/reading-path.svg. Copy the entire root folder to a new location, preserving its internal structure. The path from docs/overview.md to the image still has the same relationship: up once, then into assets/.
Next, move only docs/overview.md into another folder. The relative image path is still written in the file, but its new base directory is different. It no longer identifies the asset in the original package. Finally, leave the document in place and rename assets/reading-path.svg without changing its reference: the filename no longer matches. These outcomes follow ordinary relative-path resolution; actual rendering still depends on the app and its access to the folder.
The broken/example.md file intentionally links to a missing target. It is an exercise, not a packaging accident. Compare that deliberate failure with the two breakages you created.
What the experiment teaches
Portability comes from preserving relationships, not from the .md extension alone. A manifest and a root README make missing pieces easier to notice. Absolute paths tied to one person’s Mac are more fragile still. For repairs, use the relative-link guide; for designing the folder from the start, read portable linked Markdown.
No timing, customer data or competitor behavior was measured here. Anyone can repeat the file operations with the downloadable source.