1 INTRODUCTION  
1.1 Linear polarization and Faraday rotation definitions  
2 DATA ANALYSIS  
2.1 Initial LoTSS data products  
2.2 RM and polarization data products  
2.3 RM Grid catalogue construction  
3 RESULTS  
3.1 LoTSS-DR2 RM Grid  
3.2 Comparison with other RM catalogues  
3.3 Optical identification and redshifts  
3.4 The nature of polarized sources at MHz frequencies  
3.5 Pulsar identifications  
4 SUMMARY  
4.1 Future LoTSS RM Grid enhancements