Several small 3rd party libraries are included directly but there are some things such as plug-in SDKs that you have to install.

Some optional dependencies can be downloaded and built locally using scripts in the Extras and IGraphics sub-folders. Alternatively, you can download pre-built versions that are generated by continuous integration servers.

The subfolder "Build" should contain these built libraries with sub-folders for each platform.

Pre-built macOS dependencies can be downloaded here: IPLUG2_DEPS_MAC.zip

and should be extracted so it looks like this...

iPlug2/Dependencies/Build/src/
iPlug2/Dependencies/Build/mac/
iPlug2/Dependencies/Build/mac/bin
iPlug2/Dependencies/Build/mac/include
iPlug2/Dependencies/Build/mac/lib
iPlug2/Dependencies/Build/mac/share

Pre-built iOS dependencies can be downloaded here: IPLUG2_DEPS_IOS.zip

and should be extracted so it looks like this...

iPlug2/Dependencies/Build/src/
iPlug2/Dependencies/Build/ios/lib/arm64
iPlug2/Dependencies/Build/ios/lib/x86

Pre-built Windows dependencies can be downloaded here: IPLUG2_DEPS_WIN.zip

iPlug2/Dependencies/Build/src/
iPlug2/Dependencies/Build/win/Debug/x86
iPlug2/Dependencies/Build/win/Release/x86
iPlug2/Dependencies/Build/win/Debug/x64
iPlug2/Dependencies/Build/win/Release/x64