"textual explanation" is a correct and usable phrase in written English.
You could use it when you are trying to explain something via written text, such as an email or a document. For example, "I have included a textual explanation of the different steps in the process for your reference."
These photographs don't need a lot of textual explanation.
Gorogoa (iOS, Windows, Switch) Many games defy textual explanation, but Gorogoa is a special case.
Students write a textual explanation of a graph clipped from The New York Times.
It ran in last Friday's English-language newspaper without any other textual explanation or accompanying article.
SFC is supplemented with textual explanation of its guards and actions, written in Structured Text.
Each pattern is described by its IFML model, an exemplary UI rendering and a textual explanation of its behavior.
The museum also plans to use red borders on textual explanations that are graphic or violent to alert guests in advance.
Rather than viewing images as "visual aids" to accompany textual explanations, students are responsible for drawing conclusions from image data.
The exhibition includes ancient and rare books, maps and scrolls, and textual explanations that guide visitors through 5,000 years of Chinese history.
They are an integral part of an ongoing research and educational project which includes lengthy textual explanations that accompany each picture.
That's especially true in the scenes in which Ms. Jolie switches into full-on expository mode, putting dry, plodding words into the characters' mouths that would work better in the kind of on-screen textual explanations, with their snippets of history and politics, that open and close the movie.
