mmdc not generating labels for SVG outputs

[radupotop]

Describe the bug

mmdc does not generate labels when outputting SVG files.
This happens for flow charts and class charts on my machine, but not for sequence diagrams for example.

To Reproduce
Steps to reproduce the behavior:

echo "graph TD; THIS-->THAT; THAT-->THIS" | mmdc -i -

Output:

Expected behavior

The graph should include labels like so:

Desktop (please complete the following information):

• Linux x86_64 6.8.9
• gtk2 2.24.33-3
• gtk3 3.24.41-1
• gtk4 4.14.4-1
• cairo 1.18.0-2
• pango 1.52.2-1

My gut feeling is this is related to rendering on my machine (pango, cairo, etc).

[radupotop]

Opened a corresponding issue here with librsvg:
https://gitlab.gnome.org/GNOME/librsvg/-/issues/1082

[radupotop]

It looks like this is an issue with mermaid-cli after all:

This SVG uses foreignObject to embed HTML text. Supporting this would basically involve having a whole HTML renderer inside librsvg. Please tell mermaid-cli to use SVG text elements instead.