I cannot make the source maps (generated from typescript 3.5) active in a extension (background, popup or content). You can see my example extension if you unzip the attached example. When opening one of the .js files (e.g. base.js as used in the background), chrome notices "source map detected" (see the .png file), but I cannot load .ts file from "Page". If I load it from the Filesystem, breakpoints set in .ts file are not active. The setting "enable javascript source files" is on. web_accessible_resources includes "*". Chrome for Windows 10 x64 is version 75.
Thanks, Jože