Umlauts in copyrights are removed from output files

Hi,
when scanning files with umlauts, they are converted to non umlauts. It should be better to keep them in the original form.
Sample file:
https://chromium.googlesource.com/native_client/nacl-newlib/+/master/newlib/libc/time/strptime.c
Output:
"holders": [
{
"value": "Kungliga Tekniska Hogskolan (Royal Institute of Technology, Stockholm, Sweden).",
"start_line": 2,
"end_line": 4
}
],
"copyrights": [
{
"value": "Copyright (c) 1999 Kungliga Tekniska Hogskolan (Royal Institute of Technology, Stockholm, Sweden).",
"start_line": 2,
"end_line": 4
}
],

The right output would be ... Högskolan ...