You may find that when downloading or exporting assets some characters are replaced with an underscore "_". This is because every OS has a set of characters that cannot be included in a filename. Since Asset Bank files can be downloaded or unzipped to a large number of operating systems Asset Bank will convert most characters that aren't alphanumeric to an underscore.
In general, it is good practice not to use non-alphanumeric characters in filenames. The characters that Asset Bank supports are dot ".", hyphen "-" and underscore "_".