TYPO3 Core

Why do you have the fileadmin under the typo3 folder, is the question. Or did I miss something?

Yes, this is in fact not a bug.
The fileadmin folder really is at [packagename]/fileadmin and not [packagename]/typo3/fileadmin.

i actually misspelled the link typo3 generates:
if typo3 is installed under "/htdocs/TYPO3/[packagename]/", the link to a file would be "htdocs/[packagename]/fileadmin/file.xxx" instead of "htdocs//TYPO3/[packagename]/fileadmin/file.xxx".
of course, the fileadmin directory which i had referred to resides in the package's root folder.

I can still reproduce this with 3.7, and in a situation described in #0000306:

If the T3 installation is in some subdir of the webspace, then t3lib_div::getIndpEnv('TYPO3_DOCUMENT_ROOT') does not return the proper dir, but one level above, e.g. my site is located here: /home/www/box/public_html/beta, TYPO3_DOC_ROOT returns only /home/www/box/public_html

To make things worse, the url returned by linkWrapFile() is /beta/fileadmin/somedir/somefile.txt which does work if public_html is used for a proper (sub-)domain, but not if it user webspace, i.e. mydomain.com/~box

One solution would be to fix t3lib_div::getIndpEnv('TYPO3_DOCUMENT_ROOT') AND prefix the path with t3lib_div::getIndpEnv('TYPO3_SITE_URL')

Seems like it is not trivial, discuss it on -dev?

could not be reproduced during Bug Day 07/2008