in Content/scripts/git/git.cake [7:19]
public static string GetTagFromBranchName(string branchName) {
var result = (branchName ?? "alpha")
.ToLower()
.Replace(" ", "-");
var regex = new Regex("($0|[^0-9A-Za-z-])");
result = regex.Replace(result, String.Empty);
regex = new Regex("--+");
result = regex.Replace(result, "-").Substring(0, result.Length > MAX_TAG_LENGTH ? MAX_TAG_LENGTH : result.Length);
return result;
}