This bit is also known as 0x1000 in numeric mode.
The interpretation of this bit depends on whether the object is an actual file or a directory. For a regular file, this bit means that an executable should be pre-loaded into swap space even before it is run the first time. This allows for faster load time (most of the work is already done) when the executable is actually needed. However, this intepretation is deprecated in newer systems.
This bit for a directory has a different meaning. For a directory, it protects the contained files from being removed or renamed by users other than the user owner of the files. In this context, this bit is often called the “restricted deletion flag”. This is particularly helpful for folders that are typically shared among users of a system, such as /tmp.
The sticky bit has a symbol of t.