php - How to check where extension files are placed?

Question

I used php -m to see that the following extensions are installed. I want to find where these extension files are. I saw that the /usr/lib/php/20151012 folder is all in the second picture. The extensions of those files should be in dll format. Why are there all files in so format here? But everything to be loaded in the php.ini configuration file is in dll format

;extension=php_bz2.dll
;extension=php_curl.dll
;extension=php_fileinfo.dll
;extension=php_ftp.dll
extension=php_gd2.dll
;extension=php_gettext.dll
;extension=php_gmp.dll
;extension=php_intl.dll
;extension=php_imap.dll
;extension=php_interbase.dll
;extension=php_ldap.dll
;extension=php_mbstring.dll

Answer 1

The Linux platform has .so files, and the Windows platform has .dll files!