--- a/taskcluster/taskgraph/transforms/job/mozharness.py
+++ b/taskcluster/taskgraph/transforms/job/mozharness.py
@@ -195,16 +195,17 @@ def mozharness_on_generic_worker(config,
     }]
 
     docker_worker_add_gecko_vcs_env_vars(config, job, taskdesc)
 
     env = worker['env']
     env.update({
         'MOZ_BUILD_DATE': config.params['moz_build_date'],
         'MOZ_SCM_LEVEL': config.params['level'],
+        'MOZ_SIMPLE_PACKAGE_NAME': 'target',
     })
 
     if not job['attributes']['build_platform'].startswith('win'):
         raise Exception(
             "Task generation for mozharness build jobs currently only supported on Windows"
         )
 
     mh_command = [r'c:\mozilla-build\python\python.exe']

--- a/taskcluster/taskgraph/transforms/job/mozharness_test.py
+++ b/taskcluster/taskgraph/transforms/job/mozharness_test.py
@@ -188,19 +188,17 @@ def mozharness_test_on_generic_worker(co
             'name': 'public/test_info',
             'path': 'build/blobber_upload_dir',
             'type': 'directory'
         })
 
     build_platform = taskdesc['attributes']['build_platform']
     build_type = taskdesc['attributes']['build_type']
 
-    if build_platform.startswith('win'):
-        target = 'firefox-{}.en-US.{}'.format(get_firefox_version(), build_platform)
-    elif build_platform == 'macosx64' and build_type == 'opt':
+    if build_platform == 'macosx64' and build_type == 'opt':
         target = 'firefox-{}.en-US.{}'.format(get_firefox_version(), 'mac')
     else:
         target = 'target'
 
     installer_url = get_artifact_url('<build>', mozharness['build-artifact-name'])
 
     test_packages_url = get_artifact_url(
         '<build>', 'public/build/{}.test_packages.json'.format(target))

--- a/taskcluster/taskgraph/transforms/tests.py
+++ b/taskcluster/taskgraph/transforms/tests.py
@@ -354,20 +354,17 @@ def set_target(config, tests):
             else:
                 target = 'target.dmg'
         elif build_platform.startswith('android'):
             if 'geckoview' in test['test-name']:
                 target = 'geckoview_example.apk'
             else:
                 target = 'target.apk'
         elif build_platform.startswith('win'):
-            target = 'firefox-{}.en-US.{}.zip'.format(
-                get_firefox_version(),
-                build_platform.split('/')[0]
-            )
+            target = 'target.zip'
         else:
             target = 'target.tar.bz2'
         test['mozharness']['build-artifact-name'] = 'public/build/' + target
         yield test
 
 
 @transforms.add
 def set_treeherder_machine_platform(config, tests):
@@ -619,19 +616,19 @@ def set_tag(config, tests):
         yield test
 
 
 @transforms.add
 def remove_linux_pgo_try_talos(config, tests):
     """linux64-pgo talos tests don't run on try."""
     def predicate(test):
         return not(
-            test['test-platform'] == 'linux64-pgo/opt'
-            and (test['suite'] == 'talos' or test['suite'] == 'awsy')
-            and config.params['project'] == 'try'
+            test['test-platform'] == 'linux64-pgo/opt' and
+            (test['suite'] == 'talos' or test['suite'] == 'awsy') and
+            config.params['project'] == 'try'
         )
     for test in filter(predicate, tests):
         yield test
 
 
 @transforms.add
 def set_test_type(config, tests):
     for test in tests:

--- a/testing/mozharness/mozharness/mozilla/building/buildbase.py
+++ b/testing/mozharness/mozharness/mozilla/building/buildbase.py
@@ -1937,22 +1937,16 @@ or run without that action (ie: --no-{ac
         yield {
             'name': 'sccache requests_not_cacheable',
             'value': stats['stats']['requests_not_cacheable'],
             'extraOptions': self.perfherder_resource_options(),
             'alertThreshold': 50.0,
             'subtests': [],
         }
 
-    def get_firefox_version(self):
-        versionFilePath = os.path.join(
-            self.query_abs_dirs()['abs_src_dir'], 'browser/config/version.txt')
-        with open(versionFilePath, 'r') as versionFile:
-            return versionFile.readline().strip()
-
     def generate_build_stats(self):
         """grab build stats following a compile.
 
         This action handles all statistics from a build: 'count_ctors'
         and then posts to graph server the results.
         We only post to graph server for non nightly build
         """
         if self.config.get('forced_artifact_build'):
@@ -1973,30 +1967,22 @@ or run without that action (ie: --no-{ac
 
         dirs = self.query_abs_dirs()
         packageName = self.query_buildbot_property('packageFilename')
 
         # if packageName is not set because we are not running in Buildbot,
         # then assume we are using MOZ_SIMPLE_PACKAGE_NAME, which means the
         # package is named one of target.{tar.bz2,zip,dmg}.
         if not packageName:
-            firefox_version = self.get_firefox_version()
             dist_dir = os.path.join(dirs['abs_obj_dir'], 'dist')
             for ext in ['apk', 'dmg', 'tar.bz2', 'zip']:
                 name = 'target.' + ext
                 if os.path.exists(os.path.join(dist_dir, name)):
                     packageName = name
                     break
-                # if we are not using MOZ_SIMPLE_PACKAGE_NAME, check for the
-                # default package naming convention
-                name = 'firefox-{}.en-US.{}.{}'.format(
-                    firefox_version, c.get('platform'), ext)
-                if os.path.exists(os.path.join(dist_dir, name)):
-                    packageName = name
-                    break
             else:
                 self.fatal("could not determine packageName")
 
         interests = ['libxul.so', 'classes.dex', 'omni.ja']
         installer = os.path.join(dirs['abs_obj_dir'], 'dist', packageName)
         installer_size = 0
         size_measurements = []