git: 269865a8eed2 - main - stand: Update comment about devdesc

The branch main has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=269865a8eed240f572472750451484feccaeeeea

commit 269865a8eed240f572472750451484feccaeeeea
Author:     Warner Losh <imp@FreeBSD.org>
AuthorDate: 2022-11-05 01:45:27 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2022-11-05 01:46:44 +0000

    stand: Update comment about devdesc
    
    How devdesc is used is opaque until much code is read. Give a more
    useful description of the theory behind it here.
    
    Sponsored by:           Netflix
---
 stand/libsa/stand.h | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/stand/libsa/stand.h b/stand/libsa/stand.h
index 5ffff54c7ca7..3b2627355ed6 100644
--- a/stand/libsa/stand.h
+++ b/stand/libsa/stand.h
@@ -170,9 +170,14 @@ extern struct devsw netdev;
 extern int errno;
 
 /*
- * Generic device specifier; architecture-dependent
- * versions may be larger, but should be allowed to
- * overlap.
+ * Generic device specifier; architecture-dependent versions may be larger, but
+ * should be allowed to overlap. The larger device specifiers store more data
+ * than can fit in the generic one that's gleaned after parsing the device
+ * string, or used in some cases to indicate wildcards that match a variety of
+ * situations based on what's on the drive itself rather than what the progammer
+ * might know in advance. Information about open files is stored in d_opendata,
+ * though what's passed into the open routine may differ from what's present
+ * after the open on some configurations.
  */
 struct devdesc {
     struct devsw	*d_dev;