handlr:tldr:8084c

This command uses a program called handlr to set the default handler for PNG files to imv-desktop.

Let's break it down further:

• handlr: This is the name of the program or command that is being executed. In this case, it is the handlr command.
• set: This is an option or argument of the handlr command. It is used to specify that we want to set a default handler for a specific file type.
• ${-png}: This is a placeholder or variable representing the file type. In this case, it is the PNG file type. When the command is executed, this placeholder will be replaced with the actual value of the file type.
• ${imv-desktop}: Similarly, this is another placeholder representing the handler program. It will be replaced with the program imv-desktop when the command is executed.

So, this command essentially sets imv-desktop as the default program or handler for PNG files, which means that whenever you open a PNG file, it will automatically be opened by imv-desktop.