This is the general format of meta data objects describing a run:

{
    "args": {"STRIPPED FOR BREVITY"}, 
    "argv": ["STRIPPED FOR BREVITY"], 
    "base_metadata": {"STRIPPED FOR BREVITY"}, 
    "format_revision": 2, 
    "log_lines": 0, 
    "mode": "regression", 
    "profiles": ["STRIPPED FOR BREVITY"], 
    "sources_size": 460498, 
    "run_completed": true, 
    "run_finish_time": "2017-07-07T10:31:13.150062", 
    "run_start_time": "2017-07-07T10:31:05.052193", 
    "test_metadata": {"STRIPPED FOR BREVITY"},
    "tlscanary_version": "3.1.0a17"
}

For comparative modes it holds both test_metadata and base_metadata. Non-comparative modes will only contain the former.

Metadata key	Description
`args`	The parsed command line arguments as dictionary
`argv`	The raw argument vector as passed on the command line
`base_metadata`	Metadata on the baseline candidate as collected by basemode.collect_worker_info(). It is only present in comparative test modes.
`format_revision`	An integer of the meta data's format revision. This is the only value that is guaranteed to be present.
`log_lines`	Number of results in the log's `data` array.
`mode`	The run mode that produced the log entry, for example "regression"
`profiles`	Array describing the Firefox profiles used for the runs
`run_completed`	A boolean value that is false if the run was interrupted
`sources_size`	Integer size of the sources set that was tested
`test_metadata`	Metadata on the test candidate as collected by basemode.collect_worker_info()
`run_finish_time`	UTC timestamp in ISO format, for example "2017-07-07T10:31:13.150062"
`run_start_time`	UTC timestamp in ISO format, for example "2017-07-07T10:31:05.052193
`tlscanary_version`	A version string like "3.1.0"

Here's the complete sample of a regression run's meta data:

{
    "args": {
        "base": "release", 
        "debug": false, 
        "filter": 1, 
        "limit": 10, 
        "mode": "regression", 
        "onecrl": "production", 
        "parallel": 4, 
        "prefs": null, 
        "prefs_base": null, 
        "prefs_test": null, 
        "requestsperworker": 50, 
        "scans": 3, 
        "source": "top", 
        "test": "nightly", 
        "timeout": 10, 
        "workdir": "/Users/cruetten/.tlscanary"
    }, 
    "argv": [
        "/Users/cruetten/Documents/src/tls-canary/venv/bin/tlscanary", 
        "regression", 
        "-l", 
        "10"
    ], 
    "base_metadata": {
        "appConstants": {
            "ACCESSIBILITY": true, 
            "ANDROID_PACKAGE_NAME": "org.mozilla.firefox", 
            "ASAN": false, 
            "CAN_DRAW_IN_TITLEBAR": true, 
            "DEBUG": false, 
            "DEBUG_JS_MODULES": "", 
            "DLL_PREFIX": "lib", 
            "DLL_SUFFIX": ".dylib", 
            "E10S_TESTING_ONLY": false, 
            "HAVE_SHELL_SERVICE": true, 
            "HAVE_USR_LIB64_DIR": false, 
            "INSTALL_COMPACT_THEMES": true, 
            "INSTALL_LOCALE": "en-US", 
            "MENUBAR_CAN_AUTOHIDE": false, 
            "MOZILLA_OFFICIAL": true, 
            "MOZ_ANDROID_ACTIVITY_STREAM": false, 
            "MOZ_ANDROID_HISTORY": false, 
            "MOZ_APP_NAME": "firefox", 
            "MOZ_APP_VERSION": "54.0.1", 
            "MOZ_APP_VERSION_DISPLAY": "54.0.1", 
            "MOZ_B2G": false, 
            "MOZ_B2G_OS_NAME": "", 
            "MOZ_B2G_RIL": false, 
            "MOZ_B2G_VERSION": "1.0.0", 
            "MOZ_BUILD_APP": "browser", 
            "MOZ_CONTENT_SANDBOX": true, 
            "MOZ_CRASHREPORTER": true, 
            "MOZ_DATA_REPORTING": true, 
            "MOZ_DEV_EDITION": false, 
            "MOZ_GECKO_PROFILER": true, 
            "MOZ_GRAPHENE": false, 
            "MOZ_MACBUNDLE_NAME": "Firefox.app", 
            "MOZ_MAINTENANCE_SERVICE": false, 
            "MOZ_OFFICIAL_BRANDING": true, 
            "MOZ_PLACES": true, 
            "MOZ_REQUIRE_SIGNING": true, 
            "MOZ_SANDBOX": true, 
            "MOZ_SERVICES_CLOUDSYNC": true, 
            "MOZ_SERVICES_HEALTHREPORT": true, 
            "MOZ_SWITCHBOARD": false, 
            "MOZ_SYSTEM_NSS": false, 
            "MOZ_TELEMETRY_ON_BY_DEFAULT": false, 
            "MOZ_TELEMETRY_REPORTING": true, 
            "MOZ_TOOLKIT_SEARCH": true, 
            "MOZ_UPDATER": true, 
            "MOZ_UPDATE_CHANNEL": "release", 
            "MOZ_VERIFY_MAR_SIGNATURE": true, 
            "MOZ_WEBRTC": true, 
            "MOZ_WIDGET_GTK": false, 
            "MOZ_WIDGET_TOOLKIT": "cocoa", 
            "NIGHTLY_BUILD": false, 
            "RELEASE_OR_BETA": true, 
            "SOURCE_REVISION_URL": "https://hg.mozilla.org/releases/mozilla-release/rev/90f18f9c15f7c71c755e387cfc193974fcf8b29c", 
            "XP_UNIX": true, 
            "platform": "macosx"
        }, 
        "app_version": "54.0.1", 
        "application_ini": {
            "buildid": "20170628075643", 
            "id": "{ec8030f7-c20a-464f-9b0e-13a3a9e97384}", 
            "name": "Firefox", 
            "remotingname": "firefox", 
            "sourcerepository": "https://hg.mozilla.org/releases/mozilla-release", 
            "sourcestamp": "90f18f9c15f7c71c755e387cfc193974fcf8b29c", 
            "vendor": "Mozilla", 
            "version": "54.0.1"
        }, 
        "branch": "release", 
        "nspr_version": "NSPR 4.14", 
        "nssInfo": {
            "NSPR_MinVersion": "4.14", 
            "NSPR_Version": "4.14", 
            "NSSSMIME_MinVersion": "3.30.2", 
            "NSSSMIME_Version": "3.30.2", 
            "NSSSSL_MinVersion": "3.30.2", 
            "NSSSSL_Version": "3.30.2", 
            "NSSUTIL_MinVersion": "3.30.2", 
            "NSSUTIL_Version": "3.30.2", 
            "NSS_MinVersion": "3.30.2", 
            "NSS_Version": "3.30.2"
        }, 
        "nss_version": "NSS 3.30.2", 
        "package_origin": "https://download.mozilla.org/?product=firefox-latest&os=osx&lang=en-US", 
        "platform": "osx"
    }, 
    "format_revision": 2, 
    "log_lines": 0, 
    "mode": "regression", 
    "profiles": [
        {
            "log_part": "test_profile.zip", 
            "name": "test_profile"
        }, 
        {
            "log_part": "base_profile.zip", 
            "name": "base_profile"
        }
    ], 
    "run_completed": true, 
    "run_finish_time": "2017-07-07T10:31:13.150062", 
    "run_start_time": "2017-07-07T10:31:05.052193", 
    "sources_size": 460498, 
    "test_metadata": {
        "appConstants": {
            "ACCESSIBILITY": true, 
            "ANDROID_PACKAGE_NAME": "org.mozilla.firefox", 
            "ASAN": false, 
            "CAN_DRAW_IN_TITLEBAR": true, 
            "DEBUG": false, 
            "DEBUG_JS_MODULES": "", 
            "DLL_PREFIX": "lib", 
            "DLL_SUFFIX": ".dylib", 
            "E10S_TESTING_ONLY": true, 
            "HAVE_SHELL_SERVICE": true, 
            "HAVE_USR_LIB64_DIR": false, 
            "INSTALL_COMPACT_THEMES": true, 
            "INSTALL_LOCALE": "en-US", 
            "MENUBAR_CAN_AUTOHIDE": false, 
            "MOZILLA_OFFICIAL": true, 
            "MOZ_ADDON_SIGNING": true, 
            "MOZ_ALLOW_LEGACY_EXTENSIONS": true, 
            "MOZ_ANDROID_ACTIVITY_STREAM": false, 
            "MOZ_ANDROID_HISTORY": false, 
            "MOZ_ANDROID_MOZILLA_ONLINE": false, 
            "MOZ_APP_NAME": "firefox", 
            "MOZ_APP_VERSION": "56.0a1", 
            "MOZ_APP_VERSION_DISPLAY": "56.0a1", 
            "MOZ_B2G": false, 
            "MOZ_B2G_OS_NAME": "", 
            "MOZ_B2G_RIL": false, 
            "MOZ_B2G_VERSION": "1.0.0", 
            "MOZ_BUILD_APP": "browser", 
            "MOZ_CONTENT_SANDBOX": true, 
            "MOZ_CRASHREPORTER": true, 
            "MOZ_DATA_REPORTING": true, 
            "MOZ_DEV_EDITION": false, 
            "MOZ_GECKO_PROFILER": true, 
            "MOZ_GRAPHENE": false, 
            "MOZ_MACBUNDLE_NAME": "FirefoxNightly.app", 
            "MOZ_MAINTENANCE_SERVICE": false, 
            "MOZ_OFFICIAL_BRANDING": false, 
            "MOZ_PHOTON_ANIMATIONS": true, 
            "MOZ_PHOTON_THEME": true, 
            "MOZ_PLACES": true, 
            "MOZ_REQUIRE_SIGNING": false, 
            "MOZ_SANDBOX": true, 
            "MOZ_SERVICES_HEALTHREPORT": true, 
            "MOZ_STYLO": false, 
            "MOZ_SWITCHBOARD": false, 
            "MOZ_SYSTEM_NSS": false, 
            "MOZ_TELEMETRY_ON_BY_DEFAULT": true, 
            "MOZ_TELEMETRY_REPORTING": true, 
            "MOZ_TOOLKIT_SEARCH": true, 
            "MOZ_UPDATER": true, 
            "MOZ_UPDATE_CHANNEL": "nightly", 
            "MOZ_WEBRTC": true, 
            "MOZ_WIDGET_GTK": false, 
            "MOZ_WIDGET_TOOLKIT": "cocoa", 
            "NIGHTLY_BUILD": true, 
            "RELEASE_OR_BETA": false, 
            "SOURCE_REVISION_URL": "https://hg.mozilla.org/mozilla-central/rev/4bd7db49d22847111dff9c1dd63ed573903faa5b", 
            "XP_UNIX": true, 
            "platform": "macosx"
        }, 
        "app_version": "56.0a1", 
        "application_ini": {
            "buildid": "20170706130327", 
            "codename": "Nightly", 
            "id": "{ec8030f7-c20a-464f-9b0e-13a3a9e97384}", 
            "name": "Firefox", 
            "remotingname": "firefox", 
            "sourcerepository": "https://hg.mozilla.org/mozilla-central", 
            "sourcestamp": "4bd7db49d22847111dff9c1dd63ed573903faa5b", 
            "vendor": "Mozilla", 
            "version": "56.0a1"
        }, 
        "branch": "nightly", 
        "nspr_version": "NSPR 4.16 Beta", 
        "nssInfo": {
            "NSPR_MinVersion": "4.16 Beta", 
            "NSPR_Version": "4.16 Beta", 
            "NSSSMIME_MinVersion": "3.32 Beta", 
            "NSSSMIME_Version": "3.32 Beta", 
            "NSSSSL_MinVersion": "3.32 Beta", 
            "NSSSSL_Version": "3.32 Beta", 
            "NSSUTIL_MinVersion": "3.32 Beta", 
            "NSSUTIL_Version": "3.32 Beta", 
            "NSS_MinVersion": "3.32 Beta", 
            "NSS_Version": "3.32 Beta"
        }, 
        "nss_version": "NSS 3.32 Beta", 
        "package_origin": "https://download.mozilla.org/?product=firefox-nightly-latest&os=osx&lang=en-US", 
        "platform": "osx"
    }, 
    "tlscanary_version": "3.1.0"
}

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