ndeloof/jenkins — comment on commit 9d9020369d9152b5ab0368a60aabc81d902cff34
File:  line 0
By ndeloof:

I replaced the '/' for BUILD_TAG as I think such a character could introduce issues in post-computation of this variable, when used to generate resource files or SCM tags.
The side effect is that the BUILD_TAG may not be strictly speaking unique with a small risk of collision as you suggested.