There's a hidden file with extension .padl in my home directory and I don't know what it's for
I think I found the program that created the file: GPG Suite
In the General Terms of Distribution at https://gpgtools.org/legal
it says:
- Distribution 7.1 Our order process is conducted by our online reseller Paddle.com (Seller). Paddle.com is the Merchant of Record for all our orders. Paddle provides all customer service inquiries and handles returns.