One day, Microsoft made some computer programs and tools called "specifications" that lots of people wanted to use. But some people were worried that Microsoft might change the rules about using these specifications later on.
So, Microsoft made a promise that they would always let people use these specifications for free, even if they changed their mind later. This promise is called the "Microsoft Open Specification Promise."
Just like when your parents promise to take you to the park, Microsoft promised to let people use their computer programs and tools without any hidden fees or rules. This makes people who use these specifications feel safe and happy.