The phrase "incidental about" is not correct or commonly used in written English.
A more common phrase might be "incidental to," which means something that is related or connected to but not essential to the main topic or purpose. Example: The details about his personal life were incidental to the article's main focus on his career achievements.
Not just the set pieces but all the incidentals about south-west London life, the hopeless piano lessons and the obsession with car paintwork, the wrangles over hedges, the Waitrose runs and the twitching nets.
Along the way, there is incidental enlightenment about calculus and probability theory, about "laws" of chance, and about the precision of pi, which at the time of writing had been calculated to six billion decimal places.
What about "incidental" cocaine laced in other drugs?
All this from an apparently incidental inquiry about squirrels... It's easy to be sniffy about glossy B-movie-monger Luc Besson making a foray into socially conscious scenic issue-tainment.
The life she lived before she transformed into Angelyne seems incidental; writing about her past seems tantamount to CNN doing a story about how Santa isn't real.
She learned a lot of incidental knowledge about the French character and the last thirty years of French history from Madame Houdin.
The main gist of both ballets was evident and attractive, but I have incidental cavils about the dance texts used for both.
Though a good deal of the subject matter was evidently derived from oral tradition and thus of historical value for the period described, some of the best sagas are largely fictional; their relevance to the authors' own times mattered perhaps no less than their incidental information about the past.
Thanks to a gimmick that allowed each night's audience to serve as the jury and thereby choose the ending, the play made it to Broadway, where Rand railed against the producers' subordination of its incidental messages about the beauty of unbridled individualism.
Sly incidental jokes about Pat's place in the mediascape amuse, but The Lego Movie set the bar high for such knowing brand optimisation: Disa can't really satirise society's homogenised speed-freakery when his songs feature Ronan Keating and his animation looks scarcely finished.
Too much of "The Royal Nonesuch" is taken up with the details of Hollywood meetings, and the narrative is clogged with incidental characters, about half of whom seem to be high school friends of the author, who appear in one paragraph and disappear, forever, a paragraph later.
