1) The source is viewable (regardless of license)
2) The source is licensed under an OSI-approved license [1] (and thus also viewable)
There other definitions that I've seen as well, but I think these two are the main ones in play here.
It's clear to me from the context that slooonz is using the 2nd definition, but it's also clear from the disagreement that others are using the 1st definition (or one close to it).
Down thread [0], another user linked a page from the FSF [2]. It says:
>The official definition of “open source software” (which is published by the Open Source Initiative and is too long to include here) was derived indirectly from our criteria for free software. It is not the same; it is a little looser in some respects. Nonetheless, their definition agrees with our definition in most cases.
>However, the obvious meaning for the expression “open source software”—and the one most people seem to think it means—is “You can look at the source code.” That criterion is much weaker than the free software definition, much weaker also than the official definition of open source. It includes many programs that are neither free nor open source.
>Since the obvious meaning for “open source” is not the meaning that its advocates intend, the result is that most people misunderstand the term.
So I think the disagreements come from not defining Open Source in the same way.
And for the record, I agree (using definition 2 from above) that adding a clause to the license to restrict who can use the software would make it no longer Open Source per OSI's definition [3]:
> 5. No Discrimination Against Persons or Groups
> The license must not discriminate against any person or group of persons.
> 6. No Discrimination Against Fields of Endeavor
>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.
[0] https://news.ycombinator.com/item?id=24882631
[1] https://opensource.org/licenses
[2] https://www.gnu.org/philosophy/open-source-misses-the-point....