/sdcard/clockworkmod/backup not accessible topic

Today I've brought my first 4.4.* device, a nexus 7 from 2012. I did installed cwm (with some efforts, though. It seemed that cwm would not install if bootloader was not unlocked). In file manager I cannot acces backup path.

Code:

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root@grouper:/sdcard # cd clockworkmod
root@grouper:/sdcard/clockworkmod # ls
root@grouper:/sdcard/clockworkmod #

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In the real sdcard path I found only the log (in file manager) adb still shows nothing

Code:

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root@grouper:/storage/emulated/0 # cd clockworkmod
root@grouper:/storage/emulated/0/clockworkmod # ls
root@grouper:/storage/emulated/0/clockworkmod #

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I find the same folder structure in several paths : /storage/sdcard0, /storage/emulated/legacy.
I think i'm failing to understand the FS of kitkat. The backups are present (in cwm they are shown as being located in /sdcard/clockworkmod but I cannot find them. What am I missing here?