sgcWebSockets library has a configuration file located in source folder where contains all conditional compilations. This file is sgcVer.inc.
If you open this file, you will see there are lots of conditional defines, basically for every Delphi / C++ Builder version, there are a bunch of conditional defines. For example, for Rad Studio 10.3 there are the following:
Compiler Blocks
First directives are referred to IDE version, each IDE version has his own compiler. Usually it's not recommended to change these.
Then, there are some compilers which apply to Indy version. By default, sgcVer.inc is configured to work with Indy version provided with Rad Studio, but sometimes, is useful update Indy library to latest version. Here you can customize which is your Indy version and comment or uncomment these compiler directives.
Finally there are some compiler directives for Intraweb. In fact, Intraweb has been deprecated in later versions and by default is not needed, but if you want use Intraweb components, you can here configure which is your Intraweb version.