Front door frame advice / removing tiles

[new_to_it_all]

Hello,

I've removed some interior tiles at the foot of my aliminium front door to create a well for a coir mat. This has revealed a small plastic bar and some brick work. Does anyone know what this small plastic bar is doing? Can I remove this or is it something integral to prevent damp? Photo linked via Google Drive.


https://drive.google.com/file/d/1zw4-mt8ZM4okKeGtZ5fLZatj-OnsFgFD/view?usp=sharing

 

[Mark DM]

If referring to the black plastic strip, its a cavity closer. If you remove it the cavity will be open . Not ideal for supporting a mat tho. If there's room for ply beneath the mat then you could create adequate support if not then an option is to remove it, line the cavity with a sheet of dpm (damp proof membrane), forming a continuous tray and then fill it with concrete/ screed. Without dpm then you will create a damp issue.