Can i please get some explanation and information about the things written in the Local State file?

[HotCakeX]

The file is located here:

%localappdata%/Microsoft\Edge SxS\User Data

for Edge canary

can be viewed from browser too: edge://local-state/

some of them are obvious like this

 "browser": {
      "browser_build_version": "81.0.387.0",
      "enabled_labs_experiments": 

which show which flags are enabled.

but then i don't understand what these are for:

"experimentation_and_configuration_service_control": 2,
   "external_config_domain_actions": {
      "idl_override": {
         "applications": [ {
            "applied_policy": "ExposePrefixedEME",
            "domain": "netflix.com"
         }, {
            "applied_policy": "ExposePrefixedEME",
            "domain": "music.amazon.com"
         }, {
            "applied_policy": "ExposePrefixedEME",
            "domain": "music.amazon.de"
         }, {
            "applied_policy": "ExposePrefixedEME",
            "domain": "sling.com"
         }, {
            "applied_policy": "ExposePrefixedEME",
            "domain": "openidconnectweb.azurewebsites.net"
         } ],
         "policies": [ {
            "name": "ExposePrefixedEME",
            "type": "PrefixedEme"
         } ],
         "version": 1
      }

I'd appreciate if anyone can shed some light on it.

[#2]

@HotCakeX 

Those custom policies are enforced to ensure backwards compatibility between the new chromium based edge and legacy EdgeHTML/IE.

In this case its most likely for proprietary DRM's.

In addition to certain user agent overrides, this makes sure that a website built to use a prefixed API will continue working on the new Edge.

Browser vendors usually have prefix's for experimental technologies.

Consider the new backdrop filter CSS property. (Prefixed and normal) 

-webkit-backdrop-filter: blur(5px) saturate(125%);

backdrop-filter: blur(5px) saturate(125%);

Both works flawlessly across all major web browsers.

[#3]

Thanks, I also thought that they would be somehow related to user agents but couldn't figure out what "ExposePrefixedEME" was, still can't tbh, is it a built in policy and is there any way to access it to see more details?

also do you know what this part is?
"experimentation_and_configuration_service_control": 2"

I tried playing with it and setting it to 1 or 0 caused some of the controlled feature rollout items in Edge canary to disappear/appear. I couldn't find a reliable pattern for it though

my main reason for learning the specifics in that file is to find a way to enable features that are locked behind CFRs

[#4]

@Thraetaona 

also any insights about each of these code segments would help too

   "fre": {
      "experience_group": 0,
      "has_user_committed_selection_to_import_during_fre": false,
      "has_user_completed_fre": false,
      "has_user_seen_fre": true,
      "last_seen_fre": "81.0.387.0",
      "screens": [ "Microsoft.FRE.ScreenId.Splash", "Microsoft.FRE.ScreenId.GetStarted", "Microsoft.FRE.ScreenId.NTPLayout", "Microsoft.FRE.ScreenId.SyncToggle", "Microsoft.FRE.ScreenId.DataConsent", "Microsoft.FRE.NewProfile", "Mi0rosoft.FRE.ScreenId.SyncSignin", "Microsoft.FRE.NewProfile", "Microsoft.FRE.ScreenId.SyncSignin", "Microsoft.FRE.NewProfile", "Microsoft.FRE.ScreenId.SyncSignin", "Microsoft.FRE.NewProfile", "Microsoft.FRE.ScreenId.SyncSignin" ]
   },

   "updateclientdata": {
      "apps": {
         "gcmjkm--------------jmmjnii": {
            "cohort": "",
            "cohortname": ""
         },
         "jbfafloc-------------jkedane": {
            "cohort": "",
            "cohortname": ""
         },
         "oankkpibp--------afllipag": {
            "cohort": "",
            "cohortname": ""
         },
         "ojblfaf-----------bhejhlcim": {
            "cohort": "",
            "cohortname": ""
         }
      }
   },

 "low_entropy_source3": 6--2,
      "machine_id": 2----5,
      "ongoing_logs2": [ {
         "count_id": "4",
         "data": "----------------==",
         "hash": "M----------------o=",
         "signature": "v-------------k=",
         "timestamp": "1-----------1"

**I used ---- to censor any possible personal info.

If i'm looking at the wrong place for a way to force-enable CFRs let me know

[#5 · Accepted solution]

@HotCakeX 

You're welcome, by the way 'EME' stands for Encrypted Media Extensions.

The '"experimentation_and_configuration_service_control"' should be related to the A/B feature rollout as you've mentioned.

'"fre"' Is supposed to state weather the user has seen the splash screen that runs the first time Edge is started, I Assume it stands for something like "First Run Experience"

'"UpdateClientData"' Should be related to syncing the PWA's (apps); Judging by the pattern, it seems like I have the exact fields, although a few more entries. Not sure https://support.google.com/analytics/answer/6158745?hl=en

Most chromium fields are equal, if you want further info about the experience metrics, you could find a full list along with comments here: https://chromium.googlesource.com/chromium/src/components/metrics/+/refs/heads/master/metrics_pref_n...

Regarding CFR's, I remember having random flags added to the browser during the day despite the browser being fully updated. Hard to try and manually add those 'experiments', as the documentations are sparse at the moment.

[#6]

Thanks, that was very helpful for understanding the file :)