The process of creating SVG screenshots for our web services is plagued with numerous problems. A guide to this process is found in doc/external/images/README where one finds solutions to many of these problems, for which some require manual work before an SVG screenshot may be ready for use.
A major recurring issue is the tendency for browsers to introduce clipping and masking when printing to PDF. Most of these are innocuous and won't introduce visual artifacts, while some may cause rendering defects or unwanted sizing due to hidden extensive clipped parts.
Furthermore, most but not all objects are captured grid aligned. Due to this, it's warranted to double-check the grid alignment of certain objects where misalignment becomes very obvious, like lines and rectangles.
While it's most likely not feasible for a script to reliably perform the necessary tweaks, an autotest detecting problematic objects/paths would alleviate some manual labor, making the process more robust and less time-consuming.
https://bugzilla.mozilla.org/show_bug.cgi?id=1693989 might be of interest