Problem with rendering text

Here is an input SVG image: https://upload.wikimedia.org/wikipedia/commons/7/7d/Roll_pitch_yaw_mnemonic.svg

When rendering it, the text is off:


The SVG code contains 2 `tspan` tags nested within a `text` tag.
By removing one `tspan`, the text displays correctly.

As pointed [https://stackoverflow.com/questions/78807441/problem-with-text-rendering-using-cairosvg/78807953?noredirect=1#comment138959543_78807953](here), the problem might come from a bug in the interpretation of the `text-anchor: middle` style.

Start with the linked Roll_pitch_yaw_mnemonic.svg and compare its nested tspan elements with the attached output. Trace how text-anchor: middle is handled during rendering; done means the original SVG displays its text correctly without removing a tspan.

Written by the indexing model from the issue text.