No, it’s source available but not open source. Open source requires at minimum the license to distribute modified copies. Popular open source licenses such as MIT [1] take this further:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

This makes the license transitive so that derived works are also MIT licensed.

[1] https://en.wikipedia.org/wiki/MIT_License?wprov=sfti1#Licens...

Open Source is the same thing as Free Software, just with the different name. The term "Open Source" was coined later to emphasize the business benefits instead of the rights and freedom of the users, but the four freedoms of the Free Software Definition [1] and the ten criteria of the Open Source Definition [2] describe essentially the same thing.

[1] https://www.gnu.org/philosophy/free-sw.en.html

[2] https://opensource.org/osd

It’s is “source available” but not open source.

It's "source available" [1], not open source [2].

Words have meaning and all that.

1: https://en.wikipedia.org/wiki/Source-available_software

2: https://en.wikipedia.org/wiki/Open_source