The meaning of a small footprint.

In the welcome docs it states under CodeIgniter being right for you if...

You want a framework with a small footprint.

Could someone elaborate a little about what a small footprint means in this context?

Thanks.

The next line right after that kind of explains it:

CodeIgniter 3 has a 2MB download, including the user guide.

It's primarily about the small size of the files needed, as compared with some of the other big-name frameworks. Although not meant this way, it also applies to memory and server usage, which are pretty low compared to other frameworks.

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the actual file size of codeigniter is smaller then most full featured php frameworks.
despite its small file size codeigniter is completely self contained and does not rely in any way on any other frameworks,
or package managers. why is this relevant and important? because there are some php frameworks that are completely dependent on the symfony framework for some of their functionality. or they are dependent on package managers that may or may not be in active use a few years from now.
finally codeigniter is light weight in terms of the rules it imposes on you the developer. some people criticize this as encouraging or allowing bad practices. however in truth it makes it much faster for a new developer to get up and running with a new application. it also makes it easier to build new functionality and then refactor your code to the more 'proper' way of doing things.

Size or other opinion-based factors are not really important here ... "Small footprint" is just a fancy way to say "high performance".

Size or other opinion-based factors are not really important here ... "Small footprint" is just a fancy way to say "high performance".

... with less memory.

CodeIgniter Demo Weblog

Size or other opinion-based factors are not really important here ... "Small footprint" is just a fancy way to say "high performance".

... with less memory.

Of course, memory consumption is a performance metric.