There is something I don't understand about the use of Composer. To be clear, I am working on Windows 10 and from a wampstack package. Inside apache2\php I rubbed out any existing folder \vendor
For one project I downloaded checkdomain/holiday from Packagist. I then moved \vendor to apache2\htdocs and finally transferred it, and the other files, via FTP to an external website where everything worked OK.
Then I did exactly the same proceedure for another package phpmailer/phpmailer. However in this case \vendor contained files not only for the mailer, but also for the earlier checkdomain/holiday which I hadn't touched for several weeks.
It seems that \vendor now contains sub-folders \composer, \phpmailer and \checkdomain. The latter two sub-folders contain a file composer.json which clearly contain material relating to that project and to nothing else.
\vendor\composer however contains a file called installed.json which refers to phpmailer, checkdomain (and, in truth, to every other package which I have looked at)
I have two questions : QUESTION A If I rubbed out the folder \C:....\php\vendor before I called down a new package from Packagist by writing at the Command prompt>composer require phpmailer/phpmailer, then how did the system know anything about, and that it should download, the \checkdoain package.
QUESTION B : I clearly have information going out to the web site which the project does not need. I FTP \vendor to the website, but it contains a folder \composer which has this file called installed.json which contains information about previous projects and cannot be needed.