This is the most likely culprit for the "exclusive" tag. In Japan, Arrow aired on the satellite network AXN . Japanese broadcast standards sometimes allow for:
150MB to 400MB per episode (compressed); 1GB+ (high-definition) Cybersecurity Risks of Using Open Directories index of arrow s1 exclusive
The first season consists of 23 high-definition episodes, including the This is the most likely culprit for the "exclusive" tag
Limited-edition physical packages that included exclusive artwork, mini-comic books, or bonus discs containing additional cast interviews. The Risks of Downloading from Unverified Indexes index of arrow s1 exclusive