Form @texfig{...} at before implicitly do

\usepackage{quiver}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \usepackage{tikz}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \usetikzlibrary{spath3, intersections, backgrounds}

for users, now they are removed. Hence you must write it out explicit

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  @texfig[#:header @"
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \\usepackage{tikz}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \\usetikzlibrary{spath3, intersections, backgrounds}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  "]{
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ...
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  }
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  

The output Tex file you will get is

\documentclass[crop,dvisvgm]{standalone}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \usepackage{tikz}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \usetikzlibrary{spath3, intersections, backgrounds}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \begin{document}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ...
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  \end{document}

Since TR is a finished software (https://josem.co/the-beauty-of-finished-software/), every non-customize behaviour and already worked functions will not be removed, if you found your old cards stop working, reports to https://github.com/dannypsnl/tr/issues. I can't say there won't have any exceptions, but most problems should be counted as TR's bugs, and hence should be fixed.

Due to early experimental code, tikzcd and texfig is unstable.

The styling isn't belongs to above promise, I can only say I would avoid to touch them as possible. For example, recently I want to minimize table of content on mobile to improve UX, but except that, I will not change code of assets.

If a necessary breaking change is made, I will create a new post here that explain how to fix it.