It appears that the official chrome webstore extension by Rob W is outdated. It was last updated in 2019. 

createStandardFontBundle().pipe(
          gulp.dest(MOZCENTRAL_CONTENT_DIR + "web/standard_fonts")
        ),
        preprocessHTML("web/viewer.html", defines).pipe(
          gulp.dest(MOZCENTRAL_CONTENT_DIR + "web")
        ),
        preprocessCSS("web/viewer.css", defines)
          .pipe(
            postcss([
              autoprefixer({
                overrideBrowserslist: ["last 1 firefox versions"],
              }),
            ])
          )
          .pipe(gulp.dest(MOZCENTRAL_CONTENT_DIR + "web")),
        gulp
          .src("l10n/en-US/*.properties")
          .pipe(gulp.dest(MOZCENTRAL_L10N_DIR)),
        gulp.src("LICENSE").pipe(gulp.dest(MOZCENTRAL_EXTENSION_DIR)),
        gulp
          .src(FIREFOX_CONTENT_DIR + "PdfJsDefaultPreferences.jsm")
          .pipe(transform("utf8", preprocessDefaultPreferences))
          .pipe(gulp.dest(MOZCENTRAL_CONTENT_DIR)),
      ]);
    }
  )
);
gulp.task(
  "chromium",
  gulp.series(