The Linux FHS (Filesystem Hierarchy Standard) refers to directories of the following form:
It describes such directories as follows:
There may be one or more variants of the /lib directory on systems which support more than one binary format requiring separate libraries.
Similarly, it refers to directories:
And describes them as:
/usr/lib performs the same role as /usr/lib for an alternate binary format, except that the symbolic links /usr/lib/sendmail and /usr/lib/X11 are not required.
The FHS Wikipedia article gives the following alternate descriptions for these directories:
Alternate format essential libraries. Such directories are optional, but if they exist, they have some requirements.
Alternate format libraries, e.g. /usr/lib32 for 32-bit libraries on a 64-bit machine (optional).
I'm assuming that the string
<qual> is a mnemonic for something. Is it? If so, what does it represent?