[TYPO3-english] Fluid layout name must start with capital letter

[Karl-Heinz Fischbach]

Hi all,
I am not sure this is the right sub-forum to place the issue to.

I am with t3 already since a while.
Starting again a new website and doing all tasks from scratch to get familiar with the details and know how it works. No production use - not so far.

In most of my systems I use some filename conventions. So I tried as well with the new t3 (based on 8.7). But this failed completely.

I created a template: "av_tpl_Test.html". Fine
I used a fluid object to link to a layout:

<f:layout name="av_layout_Test" />

Expecting fluid to extend the name to "av_layout_Test.html" - but it caused an error.

After several tests I found out that the first letter of the name must be a capital letter ??????????

So this works: 
<f:layout name="Av_layout_Test" />

This is not mentioned anywhere in the docs.

Why is this the case?
Is this by design or a fault?
-- 
Regards
Karl-Heinz

Typo3: 7.6.11