Runestone Text Editor funktioniert nicht

Runestone is made by a single person with a love for text editors and a vision of building the most lightweight text editor for iPhone and iPad that still has the core features for editing code. - Syntax highlighting of many languages including HTML, JavaScript, JSON, Markdown, Swift, Python, PHP, YAML, and many more. - Select one of the twelve standard themes including popular themes like Tomorrow, Dracula, Solarized, and One Dark Pro. - Innovative find and replace for searching and modifying text while still viewing your file. - Choose font and font size, including support for custom fonts imported using another third-party app. - Show the line and column the cursor is located on. - Uses the standard document browser for an experience similar to the Files app. - Automatically close opening brackets and quotes. - Format code using Prettier. js.  Supported languages include CSS,HTML, JavaScript, JSON, PHP and more. - Choose text encoding between popular encodings like UTF-8, UTF-16, ISO Latin 1, and many more. - Enable or disable autocorrection, autocapitalization, and smart punctuation. - Disable line wrapping to allow horizontal scrolling. - Show tabs, spaces, and line breaks using a selected symbol. - Enable page guide at a specific column to easily tell when lines are getting too long. - Save file extensions and filenames that should always be treated as plain text files. - Enable soft tabs and choose the width of the tab character. - Specify whether pressing the tab key should insert a tab or indent the line. - Adjust the scaling of Markdown headings and disable highlighting of code blocks in Markdown.  A plain text editor with syntax highlighting, line numbers, search and replace, page guide, and much more.  Premium features are unlocked with a one-time in-app purchase that’s currently priced at $9. 99 USD.  Runestone was built on the open-source framework with the same name.  It's like TextEdit but more powerful and optimised for iPhone and iPad.  Pricing may vary from country to country.  Find more information on the Runestone framework at github.