# Resources

Resource extensions resolve external content through an application-provided
`ResourceResolver`. Installing an extension never grants filesystem or network
authority by itself.

## Extensions

- [Import](https://altophp.com/markdown/resources/import.md): insert escaped source code.
- [Include](https://altophp.com/markdown/resources/include.md): expand bounded Markdown resources.
- [Source](https://altophp.com/markdown/resources/source.md): display annotated source excerpts.
- [Embeds](https://altophp.com/markdown/resources/embeds.md): resolve allowlisted rich content.

Set origin, size, recursion, and content-type limits in the resolver. Read
[Security](https://altophp.com/markdown/security.md) before enabling resource-backed behavior on untrusted
input, and [Errors](https://altophp.com/markdown/errors.md) for resolution failures.