Complex sentence: Since MIT has used many licenses for software, "MIT License" is considered ambiguous, it may accurately refer to the Expat license (used for the Expat) or the X11 license (used for the X Window System by the MIT X Consortium).
Split into simpler sentences: Since MIT has used many licenses for software, "MIT License" is considered ambiguous. The particular MIT License described here may be more precisely and unambiguously referred to as the Expat license (used for the Expat) or the X11 license (used for the X Window System by the MIT X Consortium).