Source (link to git-repo or to original if based on someone elses unmodified work): https://gitlab.gnome.org/GNOME/gnome-shell/tree/e1d26ea89d2759f2e6b27441ee90249da570bea9/data/theme
Older GNOME Shells don't include the refreshed shell theme work found in the 3.34 and 3.36 series. Here's a non-official back-port of the proposed changes.
NOTE: If you have GNOME 3.32, download the original file, otherwise if you're running GNOME 3.34 and want to try out a new backport of the 3.36 changes, download the archive marked accordingly.
Please Note: This is not my work, but merely a back-port of the changes in review which can be found on the GNOME Shell Gitlab