The following Firefox probes have either expired or will expire in the next major Firefox nightly release: version 76 [1].
The following probes are expiring in Firefox version 76:
security.ui.app_menu.click#click
HTTP_NET_VS_CACHE_ONSTART_QSMALL_NORMALPRI_V2
HTTP_NET_VS_CACHE_ONSTART_QMED_NORMALPRI_V2
HTTP_NET_VS_CACHE_ONSTART_QBIG_NORMALPRI_V2
HTTP_NET_VS_CACHE_ONSTART_QSMALL_HIGHPRI_V2
HTTP_NET_VS_CACHE_ONSTART_QMED_HIGHPRI_V2
HTTP_NET_VS_CACHE_ONSTART_QBIG_HIGHPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_QSMALL_NORMALPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_QMED_NORMALPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_QBIG_NORMALPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_QSMALL_HIGHPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_QMED_HIGHPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_QBIG_HIGHPRI_V2
HTTP_NET_VS_CACHE_ONSTOP_SMALL_V2
HTTP_NET_VS_CACHE_ONSTOP_LARGE_V2
HTTP_NET_VS_CACHE_ONSTART_REVALIDATED_V2
HTTP_NET_VS_CACHE_ONSTART_NOTREVALIDATED_V2
HTTP_NET_VS_CACHE_ONSTOP_REVALIDATED_V2
HTTP_NET_VS_CACHE_ONSTOP_NOTREVALIDATED_V2
NETWORK_BACK_PRESSURE_SUSPENSION_RATE_V2
NETWORK_BACK_PRESSURE_SUSPENSION_CP_TYPE
NETWORK_BACK_PRESSURE_SUSPENSION_DELAY_TIME_MS
NETWORK_TIME_BETWEEN_NETWORK_CHANGE_EVENTS
FX_TAB_CLOSE_TIME_NO_ANIM_MS
FX_TAB_CLOSE_PERMIT_UNLOAD_TIME_MS
REFRESH_DRIVER_TICK_PHASE_WEIGHT
PRESSHELL_REQS_PER_STYLE_FLUSH
PRESSHELL_REQS_PER_LAYOUT_FLUSH
PRESSHELL_FLUSHES_PER_TICK
SHARED_MEMORY_UA_SHEETS_MAPPED_PARENT
SHARED_MEMORY_UA_SHEETS_MAPPED_PARENT_AFTER_FREEZE
SHARED_MEMORY_UA_SHEETS_MAPPED_CHILD
PRESSHELL_LAYOUT_TOTAL_MS_PER_TICK
SESSION_RESUMPTION_WITH_INTERNAL_CACHE_TIME_UNTIL_READY_MS
SESSION_RESUMPTION_WITH_EXTERNAL_CACHE_TIME_UNTIL_READY_MS
datasanitization.network_cookie_lifetimePolicy
datasanitization.privacy_sanitize_sanitizeOnShutdown
datasanitization.privacy_clearOnShutdown_cookies
datasanitization.privacy_clearOnShutdown_history
datasanitization.privacy_clearOnShutdown_formdata
datasanitization.privacy_clearOnShutdown_downloads
datasanitization.privacy_clearOnShutdown_cache
datasanitization.privacy_clearOnShutdown_sessions
datasanitization.privacy_clearOnShutdown_offlineApps
datasanitization.privacy_clearOnShutdown_siteSettings
datasanitization.privacy_clearOnShutdown_openWindows
datasanitization.session_permission_exceptions
gfx.adapter.device_id_last_seen
gfx.compositor_last_seen
qm.repositories_initialization_time
update.fix_permissions_attempted
update.startup.from_app_version
update.startup.mar_partial_size_bytes
update.startup.mar_complete_size_bytes
update.startup.intervals.check
update.startup.intervals.download_bits_partial
update.startup.intervals.download_bits_complete
update.startup.intervals.download_internal_partial
update.startup.intervals.download_internal_complete
update.startup.intervals.stage_partial
update.startup.intervals.stage_complete
update.startup.intervals.apply_partial
update.startup.intervals.apply_complete
update.startup.downloads.bits_partial_bytes
update.startup.downloads.bits_partial_seconds
update.startup.downloads.bits_complete_bytes
update.startup.downloads.bits_complete_seconds
update.startup.downloads.internal_partial_bytes
update.startup.downloads.internal_partial_seconds
update.startup.downloads.internal_complete_bytes
update.startup.downloads.internal_complete_seconds
update.session.from_app_version
update.session.mar_partial_size_bytes
update.session.mar_complete_size_bytes
update.session.intervals.check
update.session.intervals.download_bits_partial
update.session.intervals.download_bits_complete
update.session.intervals.download_internal_partial
update.session.intervals.download_internal_complete
update.session.intervals.stage_partial
update.session.intervals.stage_complete
update.session.intervals.apply_partial
update.session.intervals.apply_complete
update.session.downloads.bits_partial_bytes
update.session.downloads.bits_partial_seconds
update.session.downloads.bits_complete_bytes
update.session.downloads.bits_complete_seconds
update.session.downloads.internal_partial_bytes
update.session.downloads.internal_partial_seconds
update.session.downloads.internal_complete_bytes
update.session.downloads.internal_complete_seconds
The following probes have expired in Firefox version 75:
PDF_VIEWER_DOCUMENT_VERSION_2
PDF_VIEWER_DOCUMENT_GENERATOR_2
PDF_VIEWER_DOCUMENT_SIZE_KB
PDF_VIEWER_FONT_TYPES_2
PDF_VIEWER_EMBED_2
PDF_VIEWER_FORM_2
PDF_VIEWER_STREAM_TYPES_2
pdf.viewer.fallback_shown
pdf.viewer.print