I didn't notice at first, but, like with some other Wikipedia articles, the editors of this one have enforced the E-Prime constraint on the article itself. After the possibility occurred to me and I went back to the page to check, I only found it particularly unnatural in the initial sentence, since almost every other article begins with the sentence "[subject] is [concise definition]."
For a similar example, the "Plot Summary" section of the page about "A Void" also conforms to its subject's constraint--in that case, avoiding the letter "e": https://en.wikipedia.org/wiki/A_Void#Plot_summary
It surprises me that avoiding forms of "to be" presents such a challenge for me--particularly with this sentence. I feel that it makes my writing sound more repetitive, since I end up replacing "X is" with wordy alternatives like "I find X" or "X seems"; while I'm used to forms of "to be" appearing dozens of times in a paragraph, my replacements stand out more when overused.