YDReader 1.5.7 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The application relates to Productivity Tools. The actual developer of this free Mac application is Fuzhong Wang.
From the developer:
YDReader is a MOBi and Epub reading application with support for a variety of formats. Therefore, the tool works as a TXT, Epub, MOBi, and AZW3 reader. Your reading experience can be customized in terms of font, color, paragraph spacing, and more. Also, it supports ZIP, RAR, 7Z decompression and ZIP, 7z compression.
You may want to check out more software for Mac, such as pdf-DocPro, which might be similar to YDReader.