- * content filtering is enabled. If the client's version
- * of the document has been altered by Privoxy, the server
- * could interpret the range differently than the client
- * intended in which case the user could end up with
- * corrupted content.
+ * content filtering is enabled and the range doesn't
+ * start at byte 0.
+ *
+ * If the client's version of the document has been
+ * altered by Privoxy, the server could interpret the
+ * range differently than the client intended in which
+ * case the user could end up with corrupted content.
+ *
+ * If the range starts at byte 0 this isn't an issue
+ * so the header can pass. Partial requests like this
+ * are used to render preview images for videos without
+ * downloading the whole video.
+ *
+ * While HTTP doesn't require that range requests are
+ * honoured and the client could simply abort the download
+ * after receiving a sufficient amount of data, various
+ * clients don't handle complete responses to range
+ * requests gracefully and emit misleading error messages
+ * instead.