MSBuild Special Characters
MSBuild reserves some characters for special use in specific contexts. You only have to escape such characters if you want to use them literally in the context in which they are reserved. For example, an asterisk has special meaning only in the Include and Exclude attributes of an item definition, and in calls to CreateItem. If you want an asterisk to appear as an asterisk in one of those contexts, you must escape it. In every other context, just type the asterisk where you want it to appear.
To escape a special character, use the syntax %xx, where xx represents the ASCII hexadecimal value of the character.
The following table lists MSBuild special characters:
Referencing item lists
Conditions and other expressions
Wildcard character for file names in Include and Exclude attributes
Wildcard character for use in file names in Include and Exclude attributes