Associate a meaningful name with a specific version in the repository.

Version control tools provide a way to mark a specific instant in the history of the repository with a meaningful name.

This is not altogether different from the descriptive and memorable names we use for variables and constants in our code.  Which of the following two lines of code is easier to understand?

if (-43 == e)
if (ERR_FILE_NOT_FOUND == errorcode)

Similarly, which of the following is the most intuitive?

378
eb1637d58b1bd8f253a2f3610e8e5a7050a434ec
LAST_VERSION_BEFORE_COREY_FOULED_EVERYTHING_UP