Replace the destination as if it didn't exist before.
Don't try to keep any old permissions, replace instead of following links. This is generally useful if you're doing a "copy over" rather than a "save new version of" replace operation. You can think of it as "unlink destination" before writing to it, although the implementation may not be exactly like that. This flag can only be used with replace and its variants, including replace_contents. Since 2.20