function getPreloadLibCss() {
		var aPreloadLibCSS = BaseConfig.get({name: "sapUiPreloadLibCss", type: BaseConfig.Type.StringArray, external: true});
		if ( aPreloadLibCSS.length > 0 ) {
			// remove leading '!' (legacy) as it does not make any difference
			if ( aPreloadLibCSS[0].startsWith("!") ) {
				aPreloadLibCSS[0] = aPreloadLibCSS[0].slice(1);
			}
			// "*"  means "add all bootstrap libraries"
			if ( aPreloadLibCSS[0] === "*" ) {
				aPreloadLibCSS.shift(); // remove * (inplace)

				// The modules list also contains all configured libs
				// we prepend them now to the preloaded libs css list
				Object.keys(mLibraries).forEach(function(sLib) {
					if (!aPreloadLibCSS.includes(sLib)) {
						aPreloadLibCSS.unshift(sLib);
					}
				});
			}
		}
		return aPreloadLibCSS;
	}
Returns the list of libraries for which the library.css was preloaded.

This configuration setting specifies a list of UI libraries using the same syntax as the "libs" property,
for which the SAPUI5 core does not include the library.css stylesheet in the head of the page.
If the list starts with an exclamation mark (!), no stylesheet is loaded at all for the specified libs.
In this case, it is assumed that the application takes care of loading CSS.

If the first library's name is an asterisk (*), it will be expanded to the list of already
configured libraries.

@returns {string[]} the list of libraries for which the library.css was preloaded
@private