Lilypond 2.3.14 prints lots of debug output

[Matthias Neeracher]

During processing, I see:

[...]
Interpreting music... [8][16][24][32][34]
Preprocessing graphical objects...
Calculating line breaks... [3][6][9][12][15][18][21][24][27][30][33][34]
(
# systems:  2
real-ext #((-17.4323108826757 . 0.0) (0 . 0))
staff-ext #((0.0 . 0.0) (0 . 0))
interscore 11.3811023622047
space-letf 141.089208802364
page empty #t
spring,rod ((11.3811023622047 0.0878649508786495)) ((0 1 
-15.1560904102347))
topskip  0.0  space  158.521519685039
page-height 158.521519685039
ragged #f
force 12.9284855403349
res (0.0 158.521519685039)
positions (0.0 158.521519685039)
[...]

and several hundred lines more of this. Is there an easy way to turn 
this off?

Thanks
Matthias