To reinstall Flatpak applications from a text file containing a list of previously installed Flatpaks, follow these steps:
Create a list of your installed Flatpaks (if you don't have one):
If you are preparing for a system reinstall or migration, you can generate a list of your currently installed Flatpak applications by opening a terminal and running:
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    flatpak list --columns=application --app > flatpaks.txt
This command saves the application IDs of your installed Flatpaks (without runtimes or dependencies, as these are automatically handled during installation) into a file named flatpaks.txt. Install Flatpaks from the text file.
On your new or reinstalled system, ensure Flatpak is set up and configured with the necessary remotes (e.g., Flathub). Then, open a terminal in the directory where you saved flatpaks.txt and execute the following command:
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    xargs flatpak install -y < flatpaks.txt
This command uses xargs to read each application ID from flatpaks.txt and pass it as an argument to flatpak install -y, which will automatically install each listed Flatpak application without requiring interactive confirmation for each one.