Perl Warning: uninitialized value $prefix

Folgende Metadaten ergeben ein Perl Warning :
```
=for :application/json;q=META.json 14_SD_BELL.pm
{
"author": [
"HomeAuto_User <>",
"elektron-bbs"
],
"description": "The module is a universal module of the SIGNALduino for different bells.",
"dynamic_config": 1,
"keywords": [
"fhem-sonstige-systeme",
"fhem-hausautomations-systeme",
"fhem-mod",
"signalduino"
],
"license": [
"GPL_2"
],
"meta-spec": {
"url": "https://metacpan.org/pod/CPAN::Meta::Spec",
"version": 2
},
"name": "FHEM::SD_BELL",
"prereqs": {
"runtime": {
"requires": {
"FHEM": 5.00918623,
"FHEM::Meta": 0.001006,
"GPUtils": 0,
"lib::SD_Protocols": "0",
"perl": 5.014,
"strict": "0",
"warnings": "0"
}
},
"develop": {
"requires": {
"lib::SD_Protocols": "0",
"strict": "0",
"warnings": "0"
}
}
},
"release_status": "stable",
"resources": {
"bugtracker": {
"web": "https://github.com/RFD-FHEM/RFFHEM/issues"
},
"repository": {
"x_master": {
"type": "git",
"url": "https://github.com/RFD-FHEM/RFFHEM.git",
"web": "https://github.com/RFD-FHEM/RFFHEM/blob/master/FHEM/14_SD_BELL.pm"
},
"type": "svn",
"url": "https://svn.fhem.de/fhem",
"web": "https://svn.fhem.de/trac/browser/trunk/fhem/FHEM/14_SD_BELL.pm",
"x_branch": "trunk",
"x_filepath": "fhem/FHEM/",
"x_raw": "https://svn.fhem.de/trac/export/latest/trunk/fhem/FHEM/14_SD_BELL.pm",
"x_dev": {
"type": "git",
"url": "https://github.com/RFD-FHEM/RFFHEM.git",
"web": "https://raw.githubusercontent.com/RFD-FHEM/RFFHEM/master/FHEM/14_SD_BELL.pm",
"x_branch": "master",
"x_filepath": "FHEM/",
"x_raw": "https://github.com/RFD-FHEM/RFFHEM/blob/master/FHEM/14_SD_BELL.pm"
}
},
"x_commandref": {
"web": "https://commandref.fhem.de/#SD_BELL"
},
"x_support_community": {
"board": "Sonstige Systeme",
"boardId": "29",
"title": "FHEM - Hausautomations-Systeme >> Sonstige Systeme",
"web": "https://forum.fhem.de/index.php/board,29.0.html"
},
"x_wiki": {
"web": "https://wiki.fhem.de/wiki/SD_BELL"
}
},
"version": "v1.0.0",
"x_fhem_maintainer": [
"HomeAuto_User",
"elektron-bbs"
],
"x_fhem_maintainer_github": [
"HomeAutoUser",
"elektron-bbs"
]
}
=end :application/json;q=META.json

```

```
Error: 2021.03.22 21:30:18 1: PERL WARNING: Use of uninitialized value $prefix in regexp compilation at FHEM/Meta.pm line 2474.
```

https://github.com/fhem/pkg-Meta/blob/216ebdd6bc926594f97e5eb1951f0af6b675bef7/Meta.pm#L2474