Well those are mods.
I guess its not so much what they are as what they share
Mods and vanilla are only data in an xml file.
This is brandeburg's gate in vanilla
<Row>
<Type>BUILDING_BRANDENBURG_GATE</Type>
<BuildingClass>BUILDINGCLASS_BRANDENBURG_GATE</BuildingClass>
<Cost>750</Cost>
<PrereqTech>TECH_MILITARY_SCIENCE</PrereqTech>
<Help>TXT_KEY_WONDER_BRANDENBURG_GATE_HELP</Help>
<Description>TXT_KEY_BUILDING_BRANDENBURG_GATE</Description>
<Civilopedia>TXT_KEY_WONDER_BRANDENBURGGATE_DESC</Civilopedia>
<Quote>TXT_KEY_WONDER_BRANDENBURGGATE_QUOTE</Quote>
<ArtDefineTag>BRENDANBURG GATE</ArtDefineTag>
<MaxStartEra>ERA_INDUSTRIAL</MaxStartEra>
<SpecialistType>SPECIALIST_SCIENTIST</SpecialistType>
<GreatPeopleRateChange>2</GreatPeopleRateChange>
<NukeImmune>true</NukeImmune>
<HurryCostModifier>-1</HurryCostModifier>
<MinAreaSize>-1</MinAreaSize>
<ConquestProb>100</ConquestProb>
<Culture>3</Culture>
<DisplayPosition>2</DisplayPosition>
<IconAtlas>BW_ATLAS_2</IconAtlas>
<PortraitIndex>20</PortraitIndex>
<WonderSplashImage>WonderConceptBrandenburg.dds</WonderSplashImage>
<WonderSplashAnchor>L,T</WonderSplashAnchor>
<WonderSplashAudio>AS2D_WONDER_SPEECH_BRANDENBURG_GATE</WonderSplashAudio>
</Row>
If you add the node <SpecialistCount>1</SpecialistCount> you get one scientits to this wonder
