This was reported by @mine-cetinkaya-rundel

````markdown
---
title: "Untitled"
format: gfm
toc: true
---

# A header

# With ending dot.

# With a.dot in the middle

````

will render to
````markdown
# Untitled

- [A header](#a-header)
- [With ending dot.](#with-ending-dot.)
- [With a.dot in the middle](#with-a.dot-in-the-middle)

# A header

# With ending dot.

# With a.dot in the middle
````

The dots are not removed from the identifier produced in TOC. Pasting this markdown in Github will have unfunctional TOC

This is because in Pandoc `gfm_auto_identifiers` which remove the punctuation like on Github is only a **reader** extensions - see https://github.com/jgm/pandoc/issues/8709

This means that setting `toc: true` with GFM format does not work really - I think we could add `+gfm_auto_identifiers` to the reader extension `markdown` so that we produce valid TOC - if that is possible... 
dragonstyle
2023-03-22T11:51:57Z
cderv
bug upstream
v1.4
closed
`toc: true` with gfm does not produce valid link for Github when special char in headers
https://github.com/quarto-dev/quarto-cli/issues/4917