nix-build:tldr:5af2f

This command is using the Nix package manager to build and generate a binary package for the Firefox browser, with the sandboxing feature enabled.

Here is a breakdown of the command:

• nix-build: This is the command used to build a Nix expression, which describes the desired configuration of the package.
• '<nixpkgs>': This is the path to the Nixpkgs repository, which contains a collection of packages and their associated build instructions.
• --attr ${firefox}: This specifies the attribute of the package within the Nixpkgs repository that we want to build. ${firefox} is likely a shell variable that holds the name of the Firefox package.
• --option sandbox true: This sets the sandbox option to true, enabling the sandboxing feature during the build process. Sandbox provides a security measure by restricting the access of the package to certain resources and prevents it from causing harm to the system.

Overall, this command instructs Nix to build the Firefox package with sandboxing enabled, using the Nixpkgs repository as a reference for package definitions. The resulting binary package will be located in the Nix store, ready to be installed or used.