It seems like you have provided a key-value pair where the key is 'Fast Video Downloader 4.0.0.54 download the last version for mac' and the text is a description of the Fast Video Downloader software.

Here's what I've extracted from the text:

1. Download dozens of videos at the same time.

2. Track downloads on a simple and clear user interface.

3. Professional iOS data transfer and manager.

4. Supports various video formats (MP4, AVI, FLV, WebM, WMV, 3GP, MP3).

5. Can download live streams from certain websites.

About the Software:

1. The software is designed to allow users to download videos from video streaming websites.

2. It can also download videos from sites that use various file formats or host videos.

3. Fast Video Downloader is an online video downloader that lets you download HD videos from YouTube, Vimeo, and other famous online sites.

Change Log:

Unfortunately, there is no change log information available for version 4.0.0.21 of Fast Video Downloader yet.

Additional Information:

1. There is also a mention of another software called Free Download FastPCTools Screen Recorder that allows users to record their screen activity easily.

2. This tool can be used to record various types of moments on the screen, such as online conferences, meetings, tutorials, gaming moments, and more.

I hope this summary is helpful! If you have any specific questions or need further clarification on anything, feel free to ask.