The prebuilt files include `web/pdf_viewer.js` with some viewer APIs. Those are missing from type declarations.
console.log(
          "This is not a Git repository; using default build number."
        );
      }
      console.log("Extension build number: " + buildNumber);
      const version = config.versionPrefix + buildNumber;
      exec('git log --format="%h" -n 1', function (err2, stdout2, stderr2) {
        let buildCommit = "";
        if (!err2) {
          buildCommit = stdout2.replace("\n", "");
        }
        createStringSource(
          "version.json",
          JSON.stringify(
            {
              version,
              build: buildNumber,
              commit: buildCommit,
            },
            null,
            2
          )
        )
          .pipe(gulp.dest(BUILD_DIR))
          .on("end", done);
      });
    }
  );
}
function buildDefaultPreferences(defines, dir) {