Updating this ...
The IRS itself does not provide any efiling capability (unlike the states - both NJ and NY have websites where you can file, pay, etc.) They do have a webpage with links to private companies that offer online tax prep and filing. These services are free to those under certain AGI (60,000 or less) and have various fees for others. Some of them DO offer free filing of extensions.
I ended up using TaxACT - https://www.taxact.com/. Their free account has a limitation of only one return, but since the extension info is fairly limited, I was able to file three separate federal extensions, one after another by overwriting the info. It took about 24 hours to receive the final confirmation emails, but I had carefully PDFed the submission pages and the initial confirmation screen that said it had been transmitted in each case, so that I would have an (electronic) "paper trail".
West Orange - Open House, Sunday, 12/3, 1-4pm
3 Bd | 2Full Ba$0
Large 1 bedroom 1 bathroom in brand new luxury apartment -Plainfield, NJ
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