This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
Metadata interface is used by the File and Directory Entries API to contain information about a file system entry. This metadata includes the file's size and modification date and time.
This API has no official W3C or WHATWG specification.
BCD tables only load in the browser