Guess this can't do any harm ...
** BUT **
DO NOT attempt to modify these files, you will instantly lose your backups, the steps are 'unsupported' and there will be nothing that can be done to fix them.
Reading them , as below, will do no harm.
They are tar files, they can be opened with the netbackup tar command.
Eg.
root@womble sp1 $ ls /sp1
lost+found womble_1344930153_C1_HDR.1344930153.img
womble_1344930153_C1_F1.1344930153.img womble_1344930153_C1_HDR.1344930153.info
womble_1344930153_C1_F1.1344930153.info
root@womble sp1 $ /usr/openv/netbackup/bin/tar -tvf womble_1344930153_C1_F1.1344930153.img |pg
Blocksize = 64 records
drwxr-xr-x root/root 0 Aug 13 21:31 2012 /
drwxr-xr-x root/root 0 Aug 2 14:49 2012 /netbackup/
drwxr-xr-x root/root 0 Jul 26 08:47 2012 /netbackup/testdata/
-rw-r--r-- root/root 10 Jul 20 20:44 2012 /netbackup/testdata/file1
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file2
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file3
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file4
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file5
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file6
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file7
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file8
-rw-r--r-- root/root 10 Jul 26 08:47 2012 /netbackup/testdata/file9
Martin