For those of you wondering whether you can install international ROMs on the T-Mobile or Canadian Galaxy S5, let me tell you it is possible.
With previous Galaxy S4, doing this was possible also and with Galaxy S5, you can do the same.
This means you can install custom ROMs for SM-G900F/SM-G900I on the T-Mobile Galaxy S5 SM-G900T or Canadian Galaxy S5 SM-900W8. And yes, you should be able to install T-Mobile or Canadian custom ROMs also on international phones like SM-G900F/SM-G900I.
I might have forgotten some models here but in general, so long as you have a Qualcomm-based Galaxy S5, it should be compatible with other Qualcomm-based Galaxy S5 models.
The same doesn’t go for Sprint or Verizon Galaxy S5 as they use CDMA networks but there may be a way through custom ROMs that support multi-carrier.
For AT&T S5, this case should be the same but since AT&T Galaxy S5 has a locked bootloader, you will have to use Safestrap, which may be possible (but I have not tried it yet, I will update this page when that is the case.)
If you are wondering whether your Galaxy S5 is compatible, just leave a comment and I will do my best to give you my advice.