blobgen.NewReader returns ErrNotAgeStream when age cannot open the
data, in place of age's error, which quotes the data's first bytes. A
failed read of the header is still returned as the read error, and a
wrong key as age.NoIdentityMatchError.
Under --skip-errors, restore reports a blob that could not be
downloaded once, with the number of files that need it. Those files
are counted in the final warning, not listed; each is logged at debug
level.
Model: opus-5-5
sneak