That sources jar is a jar that contains only the source code (the .java files) corresponding to the compiled artifact. It is useful to add it as a source attachment in your IDE, to publish the sources, etc.
As it only contains sources, not compiled classes (.class files), it is of no use as a library dependency.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…