You can view your files in Gmail without downloading them to your device. Some file types, like images, are easy to preview in Gmail. Other files, like videos ...

It usually occurs when the file is downloaded from a not-so-popular vendor. You can ignore this warning without worrying much. However, if you wish to disable Open File – Security Warning ...

Users can generate & open HAR files on Google Chrome ... the log and choose “Save all as HAR with content” to download the file for troubleshooting.