This is a false positive. Please report it to the third party service so they can update their scanner.
This file is the archive containing the Akeeba Backup Restoration Script. At backup time, its contents are added at the beginning of your backup archive. When you extract the backup archive, this is extracted into the installation folder. Without it you cannot restore your site.
For what it's worth, that's been Akeeba Backup's architecture since 2009. Over the years the restoration script archive's filename has gone from abi.jpa (Akeeba Backup Installer; very early version of JoomlaPack and Akeeba Backup 3.x) to angie.jpa (Akeeba Next Generation Installer Engine; later Akeeba Backup 3.x to 9.x versions) to brs.jpa (Backup Restoration Script; Akeeba Backup 10.0 and later versions). Also, for what it's worth, the brs.jpa file has existed in Akeeba Backup for the past ten months. It's definitely not something new. Going from ANGIE to BRS was the entire reason for the major version bump from 9.x to 10.x.
Nicholas K. Dionysopoulos
Lead Developer and Director
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