MaxFileSize
Corex\Forms\Validation\Rules\MaxFileSize · class · Forms layer
An uploaded file is within its size cap (spec 081, FR-003). Written as max_size:5 — megabytes, because that is the unit the person writing a form is thinking in and a rule spec full of 5242880 invites the off-by-1024 that nobody notices until a 5 MB file is refused for being over 5 MB. Measured from the file on disk, not the size the browser reported, for the same reason {@see MimeType} reads the bytes: a declared size is a client assertion.