(If you find progress and other non-error messages irritating, you can use -q to suppress them)

(You can use the -w option to dump extensions.conf format to extensions.conf.aeldump)
LOG: lev:2 file:pbx_ael.c  line:3910 func: pbx_load_module  Starting AEL load process.
LOG: lev:2 file:pbx_ael.c  line:3917 func: pbx_load_module  AEL load process: calculated config file name './extensions.ael'.
LOG: lev:2 file:pbx_ael.c  line:3925 func: pbx_load_module  AEL load process: parsed config file name './extensions.ael'.
LOG: lev:4 file:pbx_ael.c  line:1167 func: check_label  Error: file ./extensions.ael, line 13-13: Duplicate label lab1! Previously defined at file ./extensions.ael, line 8.
LOG: lev:4 file:pbx_ael.c  line:1167 func: check_label  Error: file ./extensions.ael, line 49-49: Duplicate label ptr1! Previously defined at file ./extensions.ael, line 33.
LOG: lev:4 file:pbx_ael.c  line:3938 func: pbx_load_module  Sorry, but 0 syntax errors and 2 semantic errors were detected. It doesn't make sense to compile.
LOG: lev:4 file:ael2_parse  line:479 func: main  0 contexts, 0 extensions, 0 priorities