If you go by the OSI definition of Open Source (which, I know, not every does), then it's either open source or not. In this case, that license is not open source.
https://opensource.org/osd/
> The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.
> The license must not restrict anyone from making use of the program in a specific field of endeavor. For example, it may not restrict the program from being used in a business, or from being used for genetic research.
From CodeCov's BSL which goes directly against the above:
> You may make use of the Licensed Work, provided that you do not use the Licensed Work for a Competing Service.
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With that said, huge applaud to CodeCov for even making the code public under a BSL license, it's obviously a great step compared to status quo. I just wish they'd call it "Source Available/Public" instead of "Open Source" as many already seem to have troubles with what open source means.