The word at the end could be a typo, a search tag, or part of a longer filename (e.g., opera_mini_7.6.4_piece.apk ), but no official or widely known release includes “piece” in the name.
The phrase appears incomplete. It likely refers to a specific version (7.6.4) of the Opera Mini browser for Android, packaged as an APK file. opera mini 7.6.4 apk