Why does PHP apparently need an "external team" to "maintain" the Windows version of PHP?

In the last week, I learned, first through an e-mail on this e-mail list, and later from a news article on Slashdot, that Microsoft will soon (starting with the upcoming PHP 8) not be maintaining the Windows PHP archive of binaries/DLLs that I've been downloading regularly from the official Web site for PHP for the last "countless years" and which form the integral, mission-critical component of my entire "computer system". I never knew until now that Microsoft had any kind of involvement with, but it apparently was Microsoft who has, for some reason, paid somebody to "maintain" the Windows downloadables of PHP here: https://windows.php.net/ But why is Microsoft (or any external entity) involved with compiling Windows binaries such as php.exe and the various .DLL files for the modules? Is this not simply a job for the highly automated system that the PHP developers already have which can compile PHP for all supported platforms? What exactly is there to "maintain" that (apparently) requires manual work by a dedicated "team" or at least one person? Why isn't this simply a step in the general "build.php" script that the PHP developers execute for each release of PHP? Surely "PHP for Windows" is nothing but the standard, portable, cross-platform C code that the PHP developers write with cross-platformness in mind, compiled to binaries that run on the Windows platform? One of the main strengths of PHP is that it runs on all current OSes, and I can rest assure that the interpreter is working correctly whether I run Windows, Linux or macOS. Well, apparently until now. It sounds to me that this "maintainer" has to sit and actually write his own code, but that doesn't seem right. Surely all of the actual programming is part of the PHP developers' job, and then they simply have something like #ifdef TARGET_OS_WINDOWS blablabla? You don't mean to tell me that this PHP version for Windows is some kind of entirely separate project which duplicates some code from the "normal PHP" project and then writes a lot of custom code for Windows? I don't believe that. I must be missing something. Is this some kind of legal/licensing issue? Maybe the Microsoft compiler costs a bunch of money or something? But surely there are FOSS C compilers which build Windows binaries? I remember using one myself ages ago, called MingW32 or something like that. I never used Microsoft's own products at all myself, and I can't see why they would be required to build PHP on Windows. Especially as it's a "blind" CLI application with no messy GUI stuff to deal with. I also don't understand why this cannot be automated, and Microsoft couldn't simply "hand a license" to the PHP developers for them to include it automatically in their build script? (If they had to use the Microsoft compiler for some reason.) Would appreciate a clarification as Stack Exchange just keeps closing my questions if I try asking anything there.