- * Decrements the reference count for the lookup table entry @lte, which must be
- * inserted in the stream lookup table @table.
+ * Decrements the reference count of the single-instance stream @lte, which must
+ * be inserted in the stream lookup table @table.
+ *
+ * If the stream's reference count reaches 0, we may unlink it from @table and
+ * free it. However, we retain streams with 0 reference count that originated
+ * from WIM files (RESOURCE_IN_WIM). We do this for two reasons:
+ *
+ * 1. This prevents information about valid streams in a WIM file --- streams
+ * which will continue to be present after appending to the WIM file --- from
+ * being lost merely because we dropped all references to them.
+ *
+ * 2. Stream reference counts we read from WIM files can't be trusted. It's
+ * possible that a WIM has reference counts that are too low; WIMGAPI
+ * sometimes creates WIMs where this is the case. It's also possible that
+ * streams have been referenced from an external WIM; those streams can
+ * potentially have any reference count at all, either lower or higher than
+ * would be expected for this WIM ("this WIM" meaning the owner of @table) if
+ * it were a standalone WIM.