R包中的MD5文件用于什么?它是如何产生的?

I have noticed a file called 'MD5' is present in the directories of many R packages that I have downloaded. However I can not find a mention of this in the 'Writing R Extensions' manual. It lists the MD5 hash and filename for different files in the package. What is this file used for? Should it be something I include in my packages? How can it be generated?I have noticed a file called 'MD5' is present i