The excellent* TV show failed to alert the world to the real danger of SYNTHS AMONG US. Equip SynthVision goggles to identify any generation 3 synth, dead or alive. More reliable than toothpaste caps or toilet paper orientation.

they are among us ...

Install this mod at any time in any game and the player is given [ SynthVision ] goggles after Vault cryo wakeup. 

Also placed in an Institute and Railroad HQ container, replacements can be crafted at chemlab under utility.

When worn all known generation 3 synths (including corpses) will be highlighted until the goggles are removed or they die and unload. 

Gen 3 synths that do not have a synth death item are correctly populated on death regardless of goggles.  

The full list of known Gen 3 synths in the Commonwealth (top tip: don't look if you don't want to know):

Spoiler:  Show
`AmeliaStockton
BOSPaladinDanse
FFGoodneighbor08Sammy
Glory  
H2-22
Inst301SynthBoss (Gabriel)
Inst302B257 
Inst302F633 
inst302X418 
Inst302Y915 
Inst302Z322 
K1-98
lvlSynthCourser
Magnolia
MayorMcDonough
RECampLC01Jules 
RESceneLC01Accused (Art)
RETravelJS02_EscapedSynth (Timothy)
RogerWarwick 
ShaunChild 
Sturges
WorkshopNPCScript.IsSynth (Settler)
Z2-47

List excludes a crap-tonne of generic lvlActor G3 synths called [Synth] in the Institute interiors.`

The full list of known Gen 3 synths in Fah Haba (top tip: don't look if you don't want to know):

Spoiler:  Show
Aster Brooks Chase Cog Cole Denjen Faraday Julie Miranda Naveen Olympia  Tektus DLC03AcadiaSynthRefugeeF01 DLC03AcadiaSynthRefugeeF02 DLC03AcadiaSynthRefugeeF03 DLC03AcadiaSynthRefugeeM01 DLC03AcadiaSynthRefugeeM02 DLC03AcadiaSynthRefugeeM03

Synths in your settlement

Settlers marked at synths do absolutley nothing to your settlement happiness, production or any other useful stat. They do increase the chance of the "synth turning hostile" radiant quest via the WorkshopRatingPopulationSynths counter, but, as your settlers are protected by default; so what ? It is just set dressing for the underlying "institute bad, mmkay" Commonwealth narrative.

Configuration
If you know how to use xEdit you can configure some options:

Spoiler:  Show
(1) GlobalVariable SKK_SVGiveGoggles can be edited before the mod loads into a savegame:

Value 0 Goggles can only be crafted at Chemlab/Utility one set at at time.
Value 1 Can be crafted and a set is placed in institute & railroad containers (see pictures).
Value 2 (default) Can be crafted, are placed in institute & railroad containers and player is given a set after cryo exit for instant gratifiction.

(2) If there are other unique or persistent actors you would like to synth mark and add death item for LOLs, RP or 'mershun, xEdit FormList SKK_SVUserActorRefs to add the REFR ObjectReference (no, not the NPC_ ActorBase form) anytime as it is read every OnPlayerLoadGame.

PC manual installation

Install this mod at any point in any game as it is 100% new content and makes no changes to any existing content. As it does not touch any other stuff in your save-game, it has no load order needs.

Copy SKKSynthVision.esp, SKKSynthVision– Main.BA2 and  SKKSynthVision - Textures.BA2 to your ...\Fallout 4\Data directory and add to Plugins.txt, or enable in the Bethesda mod menu, use a mod manger or however you organise. Even though some may get lucky, SKK does not support the removal of any CreationEngine mod from an active savegame. 

Yes you can ESL flag the ESP.

Known Issues

None

(*) SKK Rating of Fallout TV show season 1 is 95/100 with a 5% debuff only applied for not including any talentless synth content.

********************************************************************************************
If you have read the comprehensive solution description and articles but still need support,
best to use the SKK Mods Discord channel discord://discord.gg/tgKNT77DC8
********************************************************************************************