Lab and RGB.
SightLine currently supports only x64 versions. 32-bit versions are not supported.
Versions for Windoiws: CS4, CS5, CS5.1, CS6, CC, CC2014, CC2015, CC2015.5, CC2017, CC2018.
Versions for Mac OS X: CC2015, CC2017, CC2018.
Windows 7 x64, Windows 8 x64, Windows 8.1 x64, Windows 10 x64.
Mac OS X 10.11 - 10.13.
1920x1080 or higher.
8 and 16 bits per channel.
Yes in Lab color mode. You can view results of correction in the plugin preview window with target color space and profile.
This is a cylindrical representation of Lab color space.
Read more about Lab and Lch in Wikipedia article.
Because Lab color space has larger gamut than RGB or CMYK.
Read more about gamuts in Wikipedia article.